Fariba Nayeri

Hepatocyte growth factor may accelerate healing in chronic leg ulcers: a pilot study

BACKGROUND : Hepatocyte growth factor (HGF) is a heparin-binding protein with mitogenic, motogenic and morphogenic activities for various cell types. The regenerative properties of HGF have been the object of several animal and in vitro studies in recent years. OBJECTIVE : To investigate the physiological and therapeutic effects of HGF on chronic leg ulcers. METHODS : HGF in gel form was locally applied, once daily for 7 days, to 15 of 19 chronic leg ulcers in 11 elderly patients. All patients had previously been treated by conventional methods and their leg ulcers had been in stable conditions for between 1 and 14 years. Any signs of allergy, discomfort or pain were reported daily. Microcirculation perfusion in the ulcers, compared to the intact contiguous skin, was determined by laser Doppler at the beginning of the study, after 1 week and again after 3 months (in seven patients). Ulcer size and characteristics were also documented. RESULTS : It was observed that microcirculatory perfusion, which might reflect the angiogenic effect of HGF, was statistically significantly correlated ( r = 0.94, p < 0.002) to ulcer area reduction in the treated ulcers. Excellent (84-100% area reduction) or partial healing (58-59%) was seen in eight out of 11 patients. No control group was included in this pilot study, which must be completed by proper control studies. CONCLUSION : This study suggests that HGF may heal chronic leg ulcers, possibly by improving the microcirculation. Proper control studies need to be performed.

Lipoxin A4 Inhibits Porphyromonas gingivalis-Induced Aggregation and Reactive Oxygen Species Production by Modulating Neutrophil-Platelet Interaction and CD11b Expression

ABSTRACT Porphyromonas gingivalis is an etiological agent that is strongly associated with periodontal disease, and it correlates with numerous inflammatory disorders, such as cardiovascular disease. Circulating bacteria may contribute to atherogenesis by promoting CD11b/CD18-mediated interactions between neutrophils and platelets, causing reactive oxygen species (ROS) production and aggregation. Lipoxin A4 (LXA4) is an endogenous anti-inflammatory and proresolving mediator that is protective of inflammatory disorders. The aim of this study was to investigate the effect of LXA4 on the P. gingivalis-induced activation of neutrophils and platelets and the possible involvement of Rho GTPases and CD11b/CD18 integrins. Platelet/leukocyte aggregation and ROS production was examined by lumiaggregometry and fluorescence microscopy. Integrin activity was studied by flow cytometry, detecting the surface expression of CD11b/CD18 as well as the exposure of the high-affinity integrin epitope, whereas the activation of Rac2/Cdc42 was examined using a glutathione S-transferase pulldown assay. The study shows that P. gingivalis activates Rac2 and Cdc42 and upregulates CD11b/CD18 and its high-affinity epitope on neutrophils, and that these effects are diminished by LXA4. Furthermore, we found that LXA4 significantly inhibits P. gingivalis-induced aggregation and ROS generation in whole blood. However, in platelet-depleted blood and in isolated neutrophils and platelets, LXA4 was unable to inhibit either aggregation or ROS production, respectively. In conclusion, this study suggests that LXA4 antagonizes P. gingivalis-induced cell activation in a manner that is dependent on leukocyte-platelet interaction, likely via the inhibition of Rho GTPase signaling and the downregulation of CD11b/CD18. These findings may contribute to new strategies in the prevention and treatment of periodontitis-induced inflammatory disorders, such as atherosclerosis.

Hepatocyte Growth Factor Levels in Cerebrospinal Fluid: A Comparison between Acute Bacterial and Nonbacterial Meningitis

The organotrophic functions of the hepatocyte growth factor (HGF) have been the subject of several studies. In the more recent studies, this function has been reported in the brain. In the present study, we have measured the levels of HGF in cerebrospinal fluid (CSF) and sera from 78 patients divided into 6 different groups according to central nervous system (CNS) infection and control. Quantitative measurements of HGF in the CSF and serum were performed by an enzyme-linked immunosorbent assay. Elevated values of CSF HGF were found in the patients with acute bacterial/probable bacterial meningitis (P<.001), compared with nonbacterial CNS infections and facial palsy, as well as with a control group without signs of CNS involvement. The values of CSF HGF were not correlated to blood-brain-barrier disruption in the groups. These observations might indicate an intrathecal production of HGF in acute bacterial/probable bacterial meningitis.

Candida glabrata prosthesis infection following pyelonephritis and septicaemia.

Candida glabrata is a well-known cause of lower urinary tract infections. Systemic infections caused by this organism are less common, but have increased dramatically in recent years. Prosthesis infection caused by C. glabrata is extremely rare. We report a case of prosthesis failure due to C. glabrata 5 y after candidaemia and pyelonephritis caused by this organism. The same C. glabrata strain was isolated from both infections, as confirmed by the random amplified polymorphic DNA (RAPD) method.

High serum hepatocyte growth factor levels in the acute stage of community-acquired infectious diseases

Acute serum levels of hepatocyte growth factor (HGF) were studied in 6 clinical groups with (i) gastroenteritis, (ii) skin and soft tissue infection, (iii) urinary tract infection, (iv) septicemia, (v) influenza, and (vi) chronic hepatitis C in comparison with a normal control group using an enzyme-linked immunosorbent assay method. We found that serum HGF levels were significantly higher in patients with acute infectious diseases (p <0.0001) compared to patients with chronic viral hepatitis and healthy controls. Serum HGF and CRP levels were correlated significantly (r = 0.65, p < 10-7). We conclude that serum HGF levels are elevated in patients with acute infectious diseases.

Hepatocyte growth factor (HGF) in fecal samples: rapid detection by surface plasmon resonance

BackgroundThe development of biosensors, based on surface plasmon resonance (SPR) technology, enables monitoring of a variety of biospecific interactions without the need for chemical-, biological- or radiological-labelled reagents.MethodWe utilised SPR to detect hepatocyte growth factor (HGF) in reconstituted faecal samples and studied samples from patients with infectious gastroenteritis (n = 20) and normal controls (n = 10). Mouse anti-human HGF monoclonal antibodies and recombinant human HGF receptor (c-Met)/Fc chimera were immobilised in flow cells of a CM5 biosensor chip.ResultsWe found that infectious gastroenteritis produced a higher signal response compared to controls, due to binding of HGF to monoclonal anti-HGF antibody as well as binding of HGF to c-Met receptor (p < 0.01). The SPR signal response correlated with results from ELISA (r = 72%, p > 0.001). The signal response decreased significantly (p < 0.05) when samples were diluted with dextran, because of reduction in both specific as well as unspecific binding of HGF to dextran. The decrease in the specific response might imply that the dextran- binding site for HGF overlaps with the antibody binding epitope, or that dextran binding induces a conformational change of the HGF molecule. Bands corresponding to HGF were found by gel electrophoresis of purified faeces in an affinity chromatography column immobilised by HGF ligands.ConclusionDetermination of HGF by SPR might be beneficial in diagnosis of acute situations that present with symptoms of gastroenteritis and may, possibly, guide appropriate medical treatments. This is to our knowledge the first report on the use of SPR for detection of HGF in faeces samples.

Hepatocyte growth factor (HGF) in patients with pneumonia : a comparison between survivors and non-survivors

Hepatocyte growth factor (HGF) is a multifunctional growth factor. After lung injury HGF is secreted in the lung and promotes reconstruction of the damaged organ. We measured, retrospectively, the serum HGF concentrations collected on admission in 55 patients with bacterial pneumonia, using an enzyme-linked immunosorbent assay (ELISA). The patients were divided into 3 groups: Group 1 was survivors with normal liver function (n = 14), Group 2 was survivors with abnormal liver function (n = 31) and Group 3 was non-survivors (n = 10). Median concentrations of HGF were elevated in Groups 1 and 2; and no statistically significant difference between these 2 groups was found. Group 3 had a median HGF concentration within the reference range, significantly lower than both Group 1 and Group 2. In addition LDH was significantly higher in non-survivors as compared with survivors. The combination of LDH and HGF concentrations discriminated between survivors and non-survivors (sensitivity 0.90 and specificity 0.96). The results support the hypothesis that increased levels of HGF might be a natural part of the healing process of lung injury, irrespective of liver involvement, and that patients without increased HGF levels, especially those with concomitant liver function impairment, may have a poor prognosis.

Clinical impact of real-time evaluation of the biological activity and degradation of hepatocyte growth factor

Hepatocyte growth factor (HGF) is essential for injury repair. Despite high HGF levels in chronic ulcers, up-regulation of HGF receptor in ulcer tissue and decreased biological activity of HGF in ulcer secretions have been observed. With a surface plasmon resonance-based method, we assessed the binding of HGF to antibodies, receptors, and the basement membrane and identified binding interactions that are indispensable for the biological activity of HGF. Recombinant HGF (rHGF) lots were tested for activity, structural integrity, and degradation, and the results were verified in an in vitro model of cell injury. Biologically active rHGF, as well as plasma from healthy volunteers, bound to heparan sulphate proteoglycan (HSPG) and to anti-HGF antibodies. Decreased binding to HSPG was the first event in rHGF degradation. This study established the feasibility of identifying patients with chronic inflammation who need exogenous HGF and of using ligand-binding assessment to evaluate rHGF lots for biological activity.

High Concentration but Low Activity of Hepatocyte Growth Factor in Periodontitis

BACKGROUND High levels of hepatocyte growth factor (HGF), a healing factor with regenerative and cytoprotective effects, are associated with inflammatory diseases, including periodontitis. HGF biologic activity requires binding to its receptors, the proto-oncogene c-Met and heparan sulfate proteoglycan (HSPG). This study investigates HGF expression and its relationship to subgingival microbiota in medically healthy individuals with and without periodontitis. METHODS Saliva, gingival crevicular fluid (GCF), and blood samples from 30 patients with severe periodontitis and 30 healthy controls were analyzed for HGF concentration using enzyme-linked immunosorbent assay and binding affinity for HSPG and c-Met using surface plasmon resonance. The regenerative effects of saliva from three patients and controls were analyzed in an in vitro model of cell injury. Subgingival plaques were analyzed for the presence of 18 bacterial species. RESULTS Patients with periodontitis showed higher HGF concentrations in saliva, GCF, and serum (P <0.001); however, the binding affinities for HSPG and c-Met were reduced in GCF and saliva (P <0.002). In contrast to the controls, saliva from patients showed no significant regenerative effect over time on gingival epithelial cells. Compared with controls, patients had a higher prevalence of periodontally related bacteria. CONCLUSIONS Higher circulatory HGF levels indicate a systemic effect of periodontitis. However, the HGF biologic activity at local inflammation sites was reduced, and this effect was associated with the amount of periodontal bacteria. Loss of function of healing factors may be an important mechanism in degenerative processes in periodontally susceptible individuals.

An in vitro model for assessment of the biological activity of hepatocyte growth factor

Hepatocyte growth factor (HGF) is a multifunctional growth factor with potent wound-healing properties that functions in the healing of chronic injuries. However, there may be a loss of HGF activity in certain chronic cases; this might be indicated by the presence of high amounts of HGF in body fluids and by the elevated expression of the HGF receptor in tissue biopsies. In such cases, a reliable means of assessing the activity of endogenous HGF would be valuable in allowing clinicians to decide if treatment with HGF would be useful. In this study, we developed an in vitro wound assay that used a mouse skin epithelial cell line to evaluate the biological activity of HGF. We showed that HGF accelerated the motility of the epithelial cells in a dose-dependent fashion with high sensitivity and specificity. This in vitro assay might be used to determine the activity of both endogenous and recombinant HGF.