Vascular endothelial growth factor synthesis in the acute phase of experimental and clinical lung injury

Role of GSDMD and VEGF in differentiating between malignant and non-malignant pleural effusions

Background

It is crucial to differentiate between benign and malignant pleural effusions while making a diagnosis. The purpose of this research was to investigate the diagnostic significance of GSDMD and VEGF in discriminating between different kinds of pleural effusion and their correlation with both progression-free and overall survivals in the malignant type.

Methods

Ninety-one pleural fluid samples, which were classified as transudates or exudates (tuberculous, para-infectious, or malignant) by pleural fluid classifications, were tested for GSDMD using sandwich ELIZA kits, and 41 of the exudative samples were randomly selected for VEGF testing. Both markers' diagnostic accuracy was assessed.

Results

The lowest level of GSDMD was associated with the transudate group (mean and SD of 2.35 ± 0.44 ng/mL) and the highest in the malignant effusion group (mean and SD of 4.38 ± 1.67 ng/mL). The specificity and sensitivity of GSDMD in the diagnosis of exudative PE were 97% and 98%, respectively (p = 0.001) with the cutoff point = 2.89). Regarding VEGF, its level was 222.3 ± 53.4 pg/ml for all studied samples where MPE (n = 21) was 261.2 ± 48.2 pg/ ml (mean ± SD), TBPE (n = 7) was 185.4 ± 6.96 pg/ml (mean ± SD), and PIPE (n = 13) was 179.3 ± 13.9 pg/ml (mean ± SD). The diagnostic accuracy of VEGF for the detection of MPE was 90% with a sensitivity of 100% and specificity of 80% and the cutoff point was 191.5 pg/ml. There were highly significant inverse correlations between progression-free survival and both GSDMD (r =− 0.531, p = 0.009) and VEGF (r = − 0.582, p = 0.006) in MPE.

Conclusion

Pleural effusion GSDMD can be an effective marker for differentiating the different kinds of PE, and VEGF levels can be a useful adjuvant marker in screening out MPE as a possible diagnosis, leading to the proper selection of patients who may benefit from more invasive procedures.

PR1P, a VEGF-stabilizing peptide, reduces injury and inflammation in acute lung injury and ulcerative colitis animal models

Acute Respiratory Distress Syndrome (ARDS) and Ulcerative Colitis (UC) are each characterized by tissue damage and uncontrolled inflammation. Neutrophils and other inflammatory cells play a primary role in disease progression by acutely responding to direct and indirect insults to tissue injury and by promoting inflammation through secretion of inflammatory cytokines and proteases. Vascular Endothelial Growth Factor (VEGF) is a ubiquitous signaling molecule that plays a key role in maintaining and promoting cell and tissue health, and is dysregulated in both ARDS and UC. Recent evidence suggests a role for VEGF in mediating inflammation, however, the molecular mechanism by which this occurs is not well understood. We recently showed that PR1P, a 12-amino acid peptide that binds to and upregulates VEGF, stabilizes VEGF from degradation by inflammatory proteases such as elastase and plasmin thereby limiting the production of VEGF degradation products (fragmented VEGF (fVEGF)). Here we show that fVEGF is a neutrophil chemoattractant in vitro and that PR1P can be used to reduce neutrophil migration in vitro by preventing the production of fVEGF during VEGF proteolysis. In addition, inhaled PR1P reduced neutrophil migration into airways following injury in three separate murine acute lung injury models including from lipopolysaccharide (LPS), bleomycin and acid. Reduced presence of neutrophils in the airways was associated with decreased pro-inflammatory cytokines (including TNF-α, IL-1β, IL-6) and Myeloperoxidase (MPO) in broncho-alveolar lavage fluid (BALF). Finally, PR1P prevented weight loss and tissue injury and reduced plasma levels of key inflammatory cytokines IL-1β and IL-6 in a rat TNBS-induced colitis model. Taken together, our data demonstrate that VEGF and fVEGF may each play separate and pivotal roles in mediating inflammation in ARDS and UC, and that PR1P, by preventing proteolytic degradation of VEGF and the production of fVEGF may represent a novel therapeutic approach to preserve VEGF signaling and inhibit inflammation in acute and chronic inflammatory diseases.

S-layer protein 2 of vaginal Lactobacillus crispatus 2029 enhances growth, differentiation, VEGF production and barrier functions in intestinal epithelial cell line Caco-2

We have previously demonstrated the ability of the human vaginal strain Lactobacillus crispatus 2029 (LC2029) for strong adhesion to cervicovaginal epithelial cells, expression of the surface layer protein 2 (Slp2), and antagonistic activity against urogenital pathogens. Slp2 forms regular two-dimensional structure around the LC2029 cells,which is secreted into the medium and inhibits intestinal pathogen-induced activation of caspase-9 and caspase-3 in the human intestinal Caco-2 cells. Here, we elucidated the effects of soluble Slp2 on adhesion of proteobacteria pathogens inducing necrotizing enterocolitis (NEC), such as Escherichia coli ATCC E 2348/69, E. coli ATCC 31705, Salmonella Enteritidis ATCC 13076, Campylobacter jejuni ATCC 29428, and Pseudomonas aeruginosa ATCC 27853 to Caco-2 cells, as well as on growth promotion, differentiation, vascular endothelial growth factor (VEGF) production, and intestinal barrier function of Caco-2 cell monolayers. Slp2 acts as anti-adhesion agent for NEC-inducing proteobacteria, promotes growth of immature Caco-2 cells and their differentiation, and enhances expression and functional activity of sucrase, lactase, and alkaline phosphatase. Slp2 stimulates VEGF production, decreases paracellular permeability, and increases transepithelial electrical resistance, strengthening barrier function of Caco-2 cell monolayers. These data support the important role of Slp2 in the early postnatal development of the human small intestine enterocytes.

Roles of lung-recruited monocytes and pulmonary Vascular Endothelial Growth Factor (VEGF) in resolving Ventilator-Induced Lung Injury (VILI)

Monocytes and vascular endothelial growth factor (VEGF) have profound effects on tissue injury and repair. In ventilator-induced lung injury (VILI), monocytes, the majority of which are Ly6C+high, and VEGF are known to initiate lung injury. However, their roles in post-VILI lung repair remain unclear. In this study, we used a two-hit mouse model of VILI to identify the phenotypes of monocytes recruited to the lungs during the resolution of VILI and investigated the contributions of monocytes and VEGF to lung repair. We found that the lung-recruited monocytes were predominantly Ly6C+low from day 1 after the insult. Meanwhile, contrary to inflammatory cytokines, pulmonary VEGF decreased upon VILI but subsequently increased significantly on days 7 and 14 after the injury. There was a strong positive correlation between VEGF expression and proliferation of alveolar epithelial cells in lung sections. The expression pattern of VEGF mRNA in lung-recruited monocytes was similar to that of pulmonary VEGF proteins, and the depletion of monocytes significantly suppressed the increase of pulmonary VEGF proteins on days 7 and 14 after VILI. In conclusion, during recovery from VILI, the temporal expression patterns of pulmonary growth factors are different from those of inflammatory cytokines, and the restoration of pulmonary VEGF by monocytes, which are mostly Ly6C+low, is associated with pulmonary epithelial proliferation. Lung-recruited monocytes and pulmonary VEGF may play crucial roles in post-VILI lung repair.

Vascular endothelial growth factor contributes to lung vascular hyperpermeability in sepsis-associated acute lung injury

Vascular endothelial growth factor (VEGF) is a prime regulator of vascular permeability. Acute lung injury (ALI) is characterized by high-permeability pulmonary edema in addition to refractory hypoxemia and diffuse pulmonary infiltrates. In this study, we examined whether VEGF can be implicated as a pulmonary vascular permeability factor in sepsis-associated ALI. We found that a great increase in lung vascular leak occurred in mice instilled intranasally with lipopolysaccharide (LPS), as assessed by IgM levels in bronchoalveolar lavage fluid. Treatment with the VEGF-neutralizing monoclonal antibody bevacizumab significantly reduced this hyperpermeability response, suggesting active participation of VEGF in non-cardiogenic lung edema associated with LPS-induced ALI. However, this was not solely attributable to excessive levels of intrapulmonary VEGF. Expression levels of VEGF were significantly reduced in lung tissues from mice with both intranasal LPS administration and cecal ligation and puncture (CLP)-induced sepsis, which may stem from decreases in non-endothelial cells-dependent VEGF production in the lungs. In support of this assumption, stimulation with LPS and interferon-γ (IFN-γ) significantly increased VEGF in human pulmonary microvascular endothelial cells (HPMECs) at mRNA and protein levels. Furthermore, a significant rise in plasma VEGF levels was observed in CLP-induced septic mice. The increase in VEGF released from HPMECs after LPS/IFN-γ challenge was completely blocked by either specific inhibitor of mitogen-activated protein kinase (MAPK) subgroups. Taken together, our results indicate that VEGF can contribute to the development of non-cardiogenic lung edema in sepsis-associated ALI due to increased VEGF secretion from pulmonary vascular endothelial cells through multiple MAPK-dependent pathways.

Endothelial Damage in Acute Respiratory Distress Syndrome

The pulmonary endothelium is a metabolically active continuous monolayer of squamous endothelial cells that internally lines blood vessels and mediates key processes involved in lung homoeostasis. Many of these processes are disrupted in acute respiratory distress syndrome (ARDS), which is marked among others by diffuse endothelial injury, intense activation of the coagulation system and increased capillary permeability. Most commonly occurring in the setting of sepsis, ARDS is a devastating illness, associated with increased morbidity and mortality and no effective pharmacological treatment. Endothelial cell damage has an important role in the pathogenesis of ARDS and several biomarkers of endothelial damage have been tested in determining prognosis. By further understanding the endothelial pathobiology, development of endothelial-specific therapeutics might arise. In this review, we will discuss the underlying pathology of endothelial dysfunction leading to ARDS and emerging therapies. Furthermore, we will present a brief overview demonstrating that endotheliopathy is an important feature of hospitalised patients with coronavirus disease-19 (COVID-19).

Montelukast, Leukotriene Inhibitor, Reduces LPS-Induced Acute Lung Inflammation and Human Neutrophil Activation

OBJECTIVES

Some pro-inflammatory lipids derived from 1 lipooxygenase enzyme are potent neutrophil chemoattractant, a cell centrally involved in acute respiratory distress syndrome (ARDS); a syndrome lacking effective treatment. Considering the beneficial effects of the leukotriene receptor inhibitor, montelukast, on other lung diseases, whether montelukast attenuates inflammation in a mouse model of ARDS, and whether it reduces LPS stimulated activation of human neutrophils was investigated.

METHODS

Thirty-five C57Bl/6 mice were distributed into control (PBS)+24h, LPS+24h (10μg/mouse), control+48h, LPS+48h, and LPS 48h+Montelukast (10mg/kg). In addition, human neutrophils were incubated with LPS (1μg/mL) and treated with montelukast (10μM).

RESULTS

Oral-tracheal administration of montelukast significantly attenuated total cells (P<.05), macrophages (P<.05), neutrophils (P<.01), lymphocytes (P<.001) and total protein levels in BAL (P<.05), as well as IL-6 (P<.05), CXCL1/KC (P<.05), IL-17 (P<.05) and TNF-α (P<.05). Furthermore, montelukast reduced neutrophils (P<.001), lymphocytes (P<.01) and macrophages (P<.01) in the lung parenchyma. In addition, montelukast restored BAL VEGF levels (P<.05). LTB4 receptor expression (P<.001) as well as NF-κB (P<.001), a downstream target of LPS, were also reduced in lung parenchymal leukocytes. Furthermore, montelukast reduced IL-8 (P<.001) production by LPS-treated human neutrophils.

CONCLUSION

In conclusion, montelukast efficiently attenuated both LPS-induced lung inflammation in a mouse model of ARDS and in LPS challenged human neutrophils.

Protective effect of bevacizumab on chemotherapy-related acute exacerbation of interstitial lung disease in patients with advanced non-squamous non-small cell lung cancer

Background

Acute exacerbation of interstitial lung disease (AE-ILD) is the most serious complication in lung cancer patients with pre-existing ILD receiving chemotherapy. The role of vascular endothelial growth factor (VEGF) in pathogenesis of AE-ILD is conflicting. The influence of bevacizumab (Bev), a monoclonal antibody against VEGF, on lung cancer patients with pre-existing ILD remains unclear. We examined the effect of Bev on reducing AE-ILD risk in non-squamous non-small cell lung cancer (NSCLC) patients receiving chemotherapy.

Methods

We analysed incidence of AE-ILD and outcomes of 48 patients with advanced non-squamous NSCLC with ILD who received first-line chemotherapy with (Bev group, n = 17) and without (non-Bev group, n = 31) Bev between July 2011 and July 2016. Gray’s test, which was competing risk analysis during the study period, was performed for both groups.

Results

The most common regimen used for first-line chemotherapy was the combination of carboplatin plus pemetrexed (PEM) in both groups. The incidences of chemotherapy-related AE-ILD 120 days after first-line chemotherapy initiation were significantly lower in the Bev than in the non-Bev groups (0% vs. 22.6%, p = 0.037, Gray’s test). However, there were no differences in development of progressive disease of lung cancer and other events as the competing risk factors of AE-ILD between the two groups. Only patients receiving PEM-containing regimens also showed a significant difference in the incidence of AE-ILD between the two groups (p = 0.044). The overall-cumulative incidence of AE-ILD during the first-line and subsequent chemotherapy was 29.2% (14 of the 48). The median progression-free survival was significantly longer in the Bev than in the non-Bev groups (8.0 vs. 4.3 months, p = 0.026).

Conclusions

The addition of Bev to chemotherapy regimens may reduce the risk of chemotherapy-related AE-ILD in patients with lung cancer.

Electronic supplementary material

The online version of this article (10.1186/s12890-019-0838-2) contains supplementary material, which is available to authorized users.

A vascular endothelial growth factor receptor gene variant is associated with susceptibility to acute respiratory distress syndrome

BACKGROUND

The acute respiratory distress syndrome (ARDS) is one of the main causes of mortality in adults admitted to intensive care units. Previous studies have demonstrated the existence of genetic variants involved in the susceptibility and outcomes of this syndrome. We aimed to identify novel genes implicated in sepsis-induced ARDS susceptibility.

METHODS

We first performed a prioritization of candidate genes by integrating our own genomic data from a transcriptomic study in an animal model of ARDS and from the only published genome-wide association study of ARDS study in humans. Then, we selected single nucleotide polymorphisms (SNPs) from prioritized genes to conduct a case-control discovery association study in patients with sepsis-induced ARDS (n = 225) and population-based controls (n = 899). Finally, we validated our findings in an independent sample of 661 sepsis-induced ARDS cases and 234 at-risk controls.

RESULTS

Three candidate genes were prioritized: dynein cytoplasmic-2 heavy chain-1, fms-related tyrosine kinase 1 (FLT1), and integrin alpha-1. Of those, a SNP from FLT1 gene (rs9513106) was associated with ARDS in the discovery study, with an odds ratio (OR) for the C allele of 0.76, 95% confidence interval (CI) 0.58-0.98 (p = 0.037). This result was replicated in an independent study (OR = 0.78, 95% CI = 0.62-0.98, p = 0.039), showing consistent direction of effects in a meta-analysis (OR = 0.77, 95% CI = 0.65-0.92, p = 0.003).

CONCLUSIONS

We identified FLT1 as a novel ARDS susceptibility gene and demonstrated that integration of genomic data can be a valid procedure to identify novel susceptibility genes. These results contribute to previous firm associations and functional evidences implicating FLT1 gene in other complex traits that are mechanistically linked, through the key role of endothelium, to the pathophysiology of ARDS.

VEGF (Vascular Endothelial Growth Factor) and Fibrotic Lung Disease

Interstitial lung disease (ILD) encompasses a group of heterogeneous diseases characterised by varying degrees of aberrant inflammation and fibrosis of the lung parenchyma. This may occur in isolation, such as in idiopathic pulmonary fibrosis (IPF) or as part of a wider disease process affecting multiple organs, such as in systemic sclerosis. Anti-Vascular Endothelial Growth Factor (anti-VEGF) therapy is one component of an existing broad-spectrum therapeutic option in IPF (nintedanib) and may become part of the emerging therapeutic strategy for other ILDs in the future. This article describes our current understanding of VEGF biology in normal lung homeostasis and how changes in its bioavailability may contribute the pathogenesis of ILD. The complexity of VEGF biology is particularly highlighted with an emphasis on the potential non-vascular, non-angiogenic roles for VEGF in the lung, in both health and disease.

Monitoring of vascular endothelial growth factor and its soluble receptor levels in early trauma

BACKGROUND

This clinical observation study aimed to investigate the relationship between the serum levels of vascular endothelial growth factor (VEGF) and its soluble receptors with the severity and the occurrence of late acute respiratory distress syndrome (ARDS) in early trauma.

METHODS

Sixty patients with multiple injuries were divided into three groups according to the Injury Severity Score (ISS) and the serum levels of VEGF, soluble VEGF receptor 1 (sVEGFR1), and sVEGFR2, were measured. Ten healthy people were recruited as controls. The incidence of late ARDS was also monitored, and its relationship to the above measures analyzed.

RESULTS

VEGF was not associated with ISS (p > 0.05); sVEGFR1 was positively associated with ISS (r = 0.459, p < 0.0001); however, sVEGFR2 was negatively associated with ISS (r = 0.510, p < 0.0001). The serum VEGF levels between the ARDS group and the non-ARDS group showed no significant difference (p > 0.05). sVEGFR1 in the ARDS group was significantly higher than that in the non-ARDS group (p < 0.0001), and sVEGFR2 in the ARDS group was significantly lower than that in the non-ARDS group (p < 0.0001).

CONCLUSION

In conclusion, the increasing of sVEGFR1 and the decreasing of sVEGFR2 in early trauma might be closely related to the occurrence of late ARDS.

LEVEL OF EVIDENCE

Prognostic study, level III.

VEGF isoforms have differential effects on permeability of human pulmonary microvascular endothelial cells

BACKGROUND

Alternative splicing of Vascular endothelial growth factor-A mRNA transcripts (commonly referred as VEGF) leads to the generation of functionally differing isoforms, the relative amounts of which have potentially significant physiological outcomes in conditions such as acute respiratory distress syndrome (ARDS). The effect of such isoforms on pulmonary vascular permeability is unknown. We hypothesised that VEGF₁₆₅a and VEGF₁₆₅b isoforms would have differing effects on pulmonary vascular permeability caused by differential activation of intercellular signal transduction pathways.

METHOD

To test this hypothesis we investigated the physiological effect of VEGF₁₆₅a and VEGF₁₆₅b on Human Pulmonary Microvascular Endothelial Cell (HPMEC) permeability using three different methods: trans-endothelial electrical resistance (TEER), Electric cell-substrate impedance sensing (ECIS) and FITC-BSA passage. In addition, potential downstream signalling pathways of the VEGF isoforms were investigated by Western blotting and the use of specific signalling inhibitors.

RESULTS

VEGF₁₆₅a increased HPMEC permeability using all three methods (paracellular and transcellular) and led to associated VE-cadherin and actin stress fibre changes. In contrast, VEGF₁₆₅b decreased paracellular permeability and did not induce changes in VE-cadherin cell distribution. Furthermore, VEGF₁₆₅a and VEGF₁₆₅b had differing effects on both the phosphorylation of VEGF receptors and downstream signalling proteins pMEK, p42/44MAPK, p38 MAPK, pAKT and peNOS. Interestingly specific inhibition of the pMEK, p38 MAPK, PI3 kinase and eNOS pathways blocked the effects of both VEGF₁₆₅a and VEGF₁₆₅b on paracellular permeability and the effect of VEGF₁₆₅a on proliferation/migration, suggesting that this difference in cellular response is mediated by an as yet unidentified signalling pathway(s).

CONCLUSION

This study demonstrates that the novel isoform VEGF₁₆₅a and VEGF₁₆₅b induce differing effects on permeability in pulmonary microvascular endothelial cells.

A new experimental model of acid- and endotoxin-induced acute lung injury in rats

The majority of the animal models of acute lung injury (ALI) are focused on the acute phase. This limits the studies of the mechanisms involved in later phases and the effects of long-term treatments. Thus the goal of this study was to develop an experimental ALI model of aspiration pneumonia, in which diffuse alveolar damage continues for 72 h. Rats were intratracheally instilled with one dose of HCl (0.1 mol/l) followed by another instillation of one dose of LPS (0, 10, 20, 30, or 40 μg/g body weight) 2 h later, which models aspiration of gastric contents that progresses to secondary lung injury from bacteria or bacterial products. The rats were euthanized at 24, 48, and 72 h after the last instillation. The results showed that HCl and LPS at all doses caused activation of inflammatory responses, increased protein permeability and apoptosis, and induced mild hypoxemia in rat lungs at 24 h postinstillation. However, this lung damage was present at 72 h only in rats receiving HCl and LPS at the doses of 30 and 40 μg/g body wt. Mortality (∼50%) occurred in the first 48 h and only in the rats treated with HCl and LPS at the highest dose (40 μg/g body wt). In conclusion, intratracheal instillation of HCl followed by LPS at the dose of 30 μg/g body wt results in severe diffuse alveolar damage that continues at least 72 h. This rat model of aspiration pneumonia-induced ALI will be useful for testing long-term effects of new therapeutic strategies in ALI.

The Vascular Endothelial Growth Factors-Expressing Character of Mesenchymal Stem Cells Plays a Positive Role in Treatment of Acute Lung Injury In Vivo

Recently, mesenchymal stem cells (MSC) have been proved to be beneficial in acute respiratory distress syndrome (ARDS). Vascular endothelial growth factor (VEGF) is an important angiogenesis factor that MSC release. However, the precise role of VEGF-expressing character of MSC in the MSC treatment for ARDS remains obscure. Here, we firstly knocked down the gene VEGF in MSC (MSC-ShVEGF) with lentiviral transduction. Then we injected the MSC-ShVEGF to rats with lipopolysaccharide-induced acute lung injury (ALI) via the tail vein. Data showed that MSC transplantation significantly increased VEGF levels in the lung, reduced lung permeability, protected lung endothelium from apoptosis, facilitated VE-cadherin recovery, controlled inflammation, and attenuated lung injury. However, VEGF gene knockdown in MSC led to relatively insufficient VEGF expression in the injured lung and significantly diminished the therapeutic effects of MSC on ALI, suggesting an important role of VEGF-expressing behavior of MSC in the maintenance of VEGF in the lung and the MSC treatment for ALI. Hence, we conclude that MSC restores the lung permeability and attenuates lung injury in rats with ALI in part by maintaining a “sufficient” VEGF level in the lung and the VEGF-expressing character of MSC plays a positive role in the therapeutic effects of MSC on ARDS.

Proteomic study of acute respiratory distress syndrome: current knowledge and implications for drug development

The acute respiratory distress syndrome (ARDS) is a common cause of acute respiratory failure, and is associated with substantial mortality and morbidity. Dozens of clinical trials targeting ARDS have failed, with no drug specifically targeting lung injury in widespread clinical use. Thus, the need for drug development in ARDS is great. Targeted proteomic studies in ARDS have identified many key pathways in the disease, including inflammation, epithelial injury, endothelial injury or activation, and disordered coagulation and repair. Recent studies reveal the potential for proteomic changes to identify novel subphenotypes of ARDS patients who may be most likely to respond to therapy and could thus be targeted for enrollment in clinical trials. Nontargeted studies of proteomics in ARDS are just beginning and have the potential to identify novel drug targets and key pathways in the disease. Proteomics will play an important role in phenotyping of patients and developing novel therapies for ARDS in the future.

A Pathophysiologic Approach to Biomarkers in Acute Respiratory Distress Syndrome

Acute respiratory distress syndrome (ARDS) is an acute-onset hypoxic condition with radiographic bilateral lung infiltration. It is characterized by an acute exudative phase combining diffuse alveolar damage and lung edema followed by a later fibroproliferative phase. Despite an improved understanding of ARDS pathobiology, our ability to predict the development of ARDS and risk-stratify patients with the disease remains limited. Biomarkers may help to identify patients at the highest risk of developing ARDS, assess response to therapy, predict outcome, and optimize enrollment in clinical trials. After a short description of ARDS pathobiology, here, we review the scientific evidence that supports the value of various ARDS biomarkers with regard to their major biological roles in ARDS-associated lung injury and/or repair. Ongoing research aims at identifying and characterizing novel biomarkers, in order to highlight relevant mechanistic explorations of lung injury and repair, and to ultimately develop innovative therapeutic approaches for ARDS patients. This review will focus on the pathophysiologic, diagnostic, and therapeutic implications of biomarkers in ARDS and on their utility to ultimately improve patient care.

Decreased VEGF Level Is Associated with Elevated Ferritin Concentration in Bronchoalveolar Lavage Fluid of Children with Interstitial Lung Diseases

BACKGROUND

A decreased level of vascular endothelial growth factor (VEGF) was previously described in bronchoalveolar lavage fluid (BALF) of adults with interstitial lung diseases (ILD) due to bronchial epithelial cell apoptosis and its proteolytic degradation. Elevated intrapulmonary ferritin was produced by alveolar cells that promoted oxidative injury in such patients.

OBJECTIVES

In this study, we analyzed the concentrations of VEGF and ferritin in BALF samples of ILD children and studied the relationship between their levels and the degree of inflammation.

METHODS

BALF and serum concentration of VEGF as well as ferritin and albumin in BALF samples were measured using enzyme-linked immunosorbent assay in children with idiopathic interstitial pneumonia (n = 16), hypersensitivity pneumonitis (n = 11) and idiopathic pulmonary hemosiderosis (n = 3). Twenty-four age- and gender-matched subjects with suspicious foreign body aspiration served as a control group.

RESULTS

VEGF per albumin levels in BALF were significantly decreased in ILD children compared to controls (1,075 [784-1,415] pg/mg albumin vs. 2,741 [1,131-4,660] pg/mg albumin, p = 0.0008). These values showed a significant negative correlation with inflammatory markers of total immune cell count in BALF (r = -0.411, p = 0.002) and serum C-reactive protein (r = -0.367, p = 0.006). Although serum VEGF was augmented in ILD children versus controls, no difference was observed among the ILD groups. In addition, BALF ferritin/albumin level (688 [188-1,571] ng/mg albumin vs. 256 [178-350] ng/mg albumin, p = 0.022) was significantly higher than normal in ILD individuals, especially in idiopathic pulmonary hemosiderosis.

CONCLUSION

Depressed VEGF and increased ferritin in BALF may reflect the severity of chronic pulmonary inflammation in altered respiratory epithelium of childhood ILD.

Proinflammatory Cytokines Increase Vascular Endothelial Growth Factor Expression in Alveolar Epithelial Cells

Vascular endothelial growth factor (VEGF) is an endothelial permeability mediator that is highly expressed in lung epithelium. In nonlung cells proinflammatory cytokines have been shown to increase VEGF expression, but their effects on lung epithelium remain unclear. We hypothesized that increases in alveolar epithelial cell VEGF RNA and protein expression occur after exposure to proinflammatory cytokines. We tested this using human alveolar epithelial cells (A549) stimulated with 5 proinflammatory cytokines. VEGF RNA expression was increased 1.4–2.7-fold in response to IL-1, IL-6, IL-8, TNF-α, or TGF-β over 6 hours, with TGF-β having the largest response. TNF-α increased VEGF RNA as early as 1 hour. A mix of IL-1, IL-6, and IL-8 had effects similar to IL-1. TNF-α increased protein expression as early as 4 hours and had a sustained effect at 16 hours, whereas IL-1 did not increase protein expression. Only VEGF₁₆₅ was present in cultured A549 cells, yet other isoforms were seen in human lung tissue. Increased expression of VEGF in alveolar epithelial cells occurs in response to proinflammatory cytokines. Increased VEGF expression likely contributes to the pathogenesis of inflammatory lung diseases and to the angiogenic phenotype of lung cancer, a disease typically preceded by chronic inflammation.

Biomarkers in acute respiratory distress syndrome

PURPOSE OF REVIEW

The article provides an overview of efforts to identify and validate biomarkers in acute respiratory distress syndrome (ARDS) and a discussion of the challenges confronting researchers in this area.

RECENT FINDINGS

Although various putative biomarkers have been investigated in ARDS, the data have been largely disappointing and the 'troponin' of ARDS remains elusive. Establishing a relationship between measurable biological processes and clinical outcomes is vital to advancing clinical trials in ARDS and expanding our arsenal of treatments for this complex syndrome.

SUMMARY

This article summarizes the current status of ARDS biomarker research and provides a framework for future investigation.

Downregulation of angiogenesis factors, VEGF and PDGF, after rapid IgE desensitization and oral immunotherapy in children with food allergy

BACKGROUND

Angiogenesis has a key role in several conditions and is regulated by several factors such as the platelet-derived growth factor (PDGF) or the vascular endothelial growth factor (VEGF). The goal of this study was to investigate the possible role of PDGF and VEGF in a group of patients with severe food allergy.

METHODS

We design a prospective longitudinal study (n = 30) with patients with persistent cow's milk proteins (CMP) allergy. After achieving a CMP rush desensitization protocol, a clinical followup including SPT and blood samples to determine sIgE, protein levels, PDGF, and VEGF-A and a panel of the most representative Th1, Th2, Treg, and Th17 cytokines were also monitored.

RESULTS

Baseline levels of PDGF and VEGF in the CMP allergic patients (1170 pg/mL and 253 pg/mL) were different compared to those nonallergic CMP control subjects (501 pg/mL and 108 pg/mL). Both PDGF and VEGF were significantly downregulated (P < 0.05) 6 months after completion of the CMP desensitization process and remained significantly decreased 12 months later.

CONCLUSION

The present study shows a significant increase of PDGF and VEGF in anaphylaxis suffering children compared to a control group. Interestingly, both VEGF and PDGF were significantly downregulated after completing a full CMP rush IgE desensitization.

Sintered anorganic bone graft increases autocrine expression of VEGF, MMP-2 and MMP-9 during repair of critical-size bone defects

This study aimed to evaluate morphometrically the bone formation and immunohistochemically the expression of vascular endothelial growth factor (VEGF) and metalloproteinase (MMP)-2 and -9 during the healing of critical-size defects treated with sintered anorganic bone (sAB). The 8-mm diameter full-thickness trephine defects created in the parietal bones of rats were filled with sAB (test group) or blood clot (CSD-control group). At 7, 14, 21, 30, 90 and 180 days postoperatively (n = 6/period) the volume of newly formed bone and total number of immunolabeled cells (Ntm) for each protein were determined. Bone formation was smaller and faster in the CSD-control group, stabilizing at 21 days (6.74 mm(3)). The peaks of VEGF, MMP-2 and MMP-9 occurred at 7 and 14 days in fibroblasts and osteoblasts, with mean reduction of 0.80 time at 21 days, keeping constant until 180 days. In the test group, sAB provided continuous bone formation between particles throughout all periods. The peak of MMP-2 was observed at 7-14 days in connective tissue cells and for VEGF and MMP-9 at 30 days in osteoblasts and osteocytes. Ntm for VEGF, MMP-2 and MMP-9 were in average, respectively, 3.70, 2.03 and 5.98 times higher than in the control group. At 180 days, newly formed bone (22.9 mm(3)) was 3.74 times greater in relation to control. The physical and chemical properties of sAB allow increased autocrine expression of VEGF, MMP-2 and MMP-9, favoring bone formation/remodeling with very good healing of cranial defects when compared to natural repair in the CSD-control.

Vascular endothelial growth factor in acute lung injury and acute respiratory distress syndrome

Acute respiratory distress syndrome (ARDS) is the most severe form of lung injury, characterised by alveolar oedema and vascular permeability, in part due to disruption of the alveolar capillary membrane integrity. Vascular endothelial growth factor (VEGF) was originally identified as a vascular permeability factor and has been implicated in the pathogenesis of acute lung injury/ARDS. This review describes our current knowledge of VEGF biology and summarises the literature investigating the potential role VEGF may play in normal lung maintenance and in the development of lung injury.

Mobilization of endothelial progenitor cells from bone marrow is impaired in a piglet model of acute respiratory distress syndrome

OBJECTIVES

To characterize the endothelial progenitor cell mobilization in the models of moderate and severe lung injury, we hypothesized that there were differences in endothelial progenitor cell levels and mobilizing cytokines between moderate and severe lung injury.

DESIGN

Prospective, randomized, and controlled experimental study.

SETTING

University research laboratory center.

SUBJECTS

Fifteen healthy piglets.

INTERVENTIONS

Piglets were randomly allocated to control, moderate lung injury (acute lung injury), and severe lung injury (acute respiratory distress syndrome) groups. Lung injury was established by intravenous infusion of oleic acid. Animals were mechanically ventilated for 24-48 hours, and then animals were weaned from ventilation and cared for until day 7.

MEASUREMENTS AND MAIN RESULTS

Endothelial progenitor cells were quantified by flow cytometry. After 24 hours, the number of endothelial progenitor cells in peripheral blood increased in the acute lung injury group but was not altered in the acute respiratory distress syndrome group compared to the control group. The number of CD34KDR, KDRCD133, and CD34KDRCD133 cells was higher in the acute lung injury group than in the acute respiratory distress syndrome group. In bone marrow, the number of CD34KDR and KDRCD133 cells was greater in acute respiratory distress syndrome animals but not altered in acute lung injury animals at 24 hours. Furthermore, plasma stromal cell-derived factor-1 and vascular endothelial growth factor concentrations were higher in acute lung injury than in acute respiratory distress syndrome at 24 hours. Matrix metalloproteinase-9 and soluble kit ligand levels in bone marrow were reduced in acute respiratory distress syndrome compared with acute lung injury. Lung CD34, KDR, and lung stromal cell-derived factor-1 messenger RNA expression were higher in the acute lung injury group than in the acute respiratory distress syndrome group. Furthermore, the expression of CD34, KDR, and CD133 messenger RNA in lung tissue was correlated with stromal cell-derived factor-1 in the lung.

CONCLUSIONS

There was a rapid release of endothelial progenitor cells from bone marrow into circulation in moderate acute lung injury, and endothelial progenitor cell mobilization was impaired in acute respiratory distress syndrome.

The fibroproliferative response in acute respiratory distress syndrome: mechanisms and clinical significance

Acute respiratory distress syndrome (ARDS) continues to be a major healthcare problem, affecting >190,000 people in the USA annually, with a mortality of 27-45%, depending on the severity of the illness and comorbidities. Despite advances in clinical care, particularly lung protective strategies of mechanical ventilation, most survivors experience impaired health-related quality of life for years after the acute illness. While most patients survive the acute illness, a subset of ARDS survivors develops a fibroproliferative response characterised by fibroblast accumulation and deposition of collagen and other extracellular matrix components in the lung. Historically, the development of severe fibroproliferative lung disease has been associated with a poor prognosis with high mortality and/or prolonged ventilator dependence. More recent studies also support a relationship between the magnitude of the fibroproliferative response and long-term health-related quality of life. The factors that determine which patients develop fibroproliferative ARDS and the cellular mechanisms responsible for this pathological response are not well understood. This article reviews our current understanding of the contribution of pulmonary dysfunction to mortality and to quality of life in survivors of ARDS, the mechanisms driving pathological fibroproliferation and potential therapeutic approaches to prevent or attenuate fibroproliferative lung disease.

Terlipressin decreases vascular endothelial growth factor expression and improves oxygenation in patients with acute respiratory distress syndrome and shock

BACKGROUND

Recent clinical data suggest that treatment with terlipressin (TP) may be more advantageous for septic shock than catecholamines. However, it is unknown whether TP would be effective for acute respiratory distress syndrome (ARDS) patients with shock.

OBJECTIVES

The aim of this study was to compare the impact of TP vs. dopamine on hemodynamic variables and vascular endothelial growth factor (VEGF) in ARDS patients with shock.

METHODS

We studied 32 ARDS patients with shock despite fluid loading, who were randomized to receive TP (16 patients) or dopamine (16 patients). TP was administered as a continuous intravenous dose of 1.3 μg/kg/h and dopamine was administered in doses up to 20 μg/kg/min to maintain a mean arterial pressure of 70 ± 5 mm Hg for 48 h. Hemodynamic changes, ratio of partial pressure of arterial oxygen to fraction of inspired oxygen (PaO(2)/FiO(2)), and VEGF were recorded prospectively.

RESULTS

There was a significant correlation between the plasma VEGF level and the lung injury score at baseline (r = 0.387, p < 0.01). VEGF concentrations significantly decreased from baseline levels in the TP group (p < 0.05) at 48 h; there was no difference in the dopamine group (p > 0.05) at 48 h vs. baseline. There was no significant difference in the tumor necrosis factor-α concentration between the groups.

CONCLUSIONS

TP treatment has the potential to inhibit VEGF and improve oxygenation in patients with shock in the early stage of ARDS.

Biomarkers in acute lung injury

Acute respiratory distress syndrome (ARDS) and acute lung injury (ALI) result in high permeability pulmonary edema causing hypoxic respiratory failure with high morbidity and mortality. As the population ages, the incidence of ALI is expected to rise. Over the last decade, several studies have identified biomarkers in plasma and bronchoalveolar lavage fluid providing important insights into the mechanisms involved in the pathophysiology of ALI. Several biomarkers have been validated in subjects from the large, multicenter ARDS clinical trials network. Despite these studies, no single or group of biomarkers has made it into routine clinical practice. New high throughput "omics" techniques promise improved understanding of the biologic processes in the pathogenesis in ALI and possibly new biomarkers that predict disease and outcomes. In this article, we review the current knowledge on biomarkers in ALI.

Expression of IL-23, VEGF and TLR2/TLR4 on mononuclear cells after exposure to Pseudomonas aeruginosa

Pseudomonas aeruginosa is a Gram-negative, aerobic bacillus causing infections of the respiratory and other organ systems in susceptible hosts. Although it does not cause pulmonary infections in immunocompetent individuals, P. aeruginosa causes chronic lung infection in individuals with cystic fibrosis and nosocomial pneumonia resulting in significant morbidity and mortality. Exogenous administration of an important P. aeruginosa virulence factor, lipase, present in P. aeruginosa culture supernatant, induces potent mononuclear cell activation leading to the production of numerous proinflammatory cytokines. In particular, P. aeruginosa culture supernatant stimulated increased proliferation of THP-1 cells and monocytes (MN). The addition of culture supernatant to THP-1 cells and MN also induced Interleukin (IL)-23 and vascular endothelial growth factor (VEGF) release in a time-dependent manner. To investigate whether any compounds present in the supernatant lipase contributed to releasing IL-23 and VEGF, the culture supernatant from P. aeruginosa containing lipase was treated with hexadecylsulfonylfluoride (AMSF). The AMSF-treated culture supernatant (CS) did not show any induction on the IL-23 and VEGF release compared to the cells treated with CS without AMSF. We also showed that Toll-like receptors (TLR)2/TLR4 are expressed in THP-1 cells and MN treated with P. aeruginosa CS in a time-dependent fashion. Flow cytometry analysis revealed a higher TLR4 and a lower TLR2 expression at 48 and 72 h of treatment. The treatment of cells with TLR4 neutralizing antibody, and to a lesser extent with TLR2 neutralizing antibody, resulted in a decrease in P. aeruginosa CS-induced IL-23 and VEGF production.

Role of heparin on serum VEGF levels and local VEGF contents in reducing the severity of experimental severe acute pancreatitis in rats

OBJECTIVE

The aims of this study were to examine the effects of prophylactic heparin treatment during taurocholate-induced pancreatitis in rats and its impact on serum VEGF levels and local VEGF contents within the pancreas.

METHODS

Severe acute pancreatitis (SAP) was induced by injecting 4% sodium taurocholate into the pancreatic duct. Heparin at a dose of 150 IU/kg s.c. was administered 30 min before the operation. The rats were sacrificed 1 h, 3 h, 6 h and 12 h (n = 5 per time point) after the onset of pancreatitis. The severity of pancreatitis, serum VEGF levels and local VEGF contents were evaluated with and without heparin pretreatment.

RESULTS

The serum VEGF levels increased at an early phase of pancreatitis, and the highest level was found at 12 h after inducing pancreatitis. The gray value of the local VEGF showed a remarkable increase from the onset of the pancreatitis. However, the gray value of VEGF did not show an increase over time but maintained a high level during the entire process. Prophylactic heparin treatment significantly improved the morphologic changes, myeloperoxidase (MPO), TNF-α and malondialdehyde (MDA) activities. Meanwhile, it decreased the serum VEGF levels and the contents of VEGF within the pancreatic tissue.

CONCLUSIONS

The present study suggests that prophylactic heparin ameliorates the severity of taurocholate-induced pancreatitis via its anti-inflammatory properties. These protective effects may be partly due to decreasing serum VEGF levels and VEGF contents within the pancreas.

Exogenous surfactant protects against endotoxin induced acute respiratory distress syndrome in rodents via vascular endothelial growth factor

Vascular endothelial growth factor (VEGF) is a potent angiogenic factor which is abundantly expressed in the normal lung and is released by numerous cell types. Using a bacteria-induced lung injury model and surfactant therapy in rats, VEGF expression in lung was investigated. Sprague Dawley male rats were divided into four groups: buffer controls; rats challenged with LPS (055:B5 E. coli); challenged with LPS and treated with porcine surfactant (P-SF); and challenged with LPS and treated with synthetic surfactant (S-SF). The expressions of VEGF, PCNA, and BrdU were studied. VEGF protein expression was decreased in comparison to the control rats, as seen by both Western immunoblot and immunohistochemistry. Protein expression of PCNA and proliferation index as determined by both PCNA and BrdU immunostaining were also seen to be decreased in the LPS-treated animals, and with the surfactant treatment the expression was increased. The downregulation of VEGF in the alveolar space may reflect the recovery from acute lung injury, which leads to the limited endothelial permeability, and may participate in the decrease in capillary number, as observed during acute respiratory distress syndrome with potentially significant clinical consequences.

Hydroxyethyl starch reduces high stretch ventilation-augmented lung injury via vascular endothelial growth factor

Disruption of epithelial and endothelial barriers found in patients with acute lung injury often results in the need for the support of mechanical ventilation. High tidal volume (V(T)) mechanical ventilation can increase lung damage through lung inflammation, but the mechanisms are unclear. We hypothesized that a colloid supply with hydroxyethyl starch would decrease neutrophil infiltration, lung edema, and vascular endothelial growth factor (VEGF) production in mice exposed to high V(T) mechanical ventilation. Male C57BL/6 mice, weighing 20 g to 25 g, were exposed to high V(T) (30 mL/kg) mechanical ventilation with room air for 1 h to 5 h and infused with 15 mL/kg/h normal saline or hydroxyethyl starch intravenously at the beginning and every 30 min during ventilation. Evans blue dye, lung wet-to-dry weight ratio, histopathologic grading of lung tissue, myeloperoxidase, and inflammatory cytokine were measured to establish the extent of lung injury. Knockdown of VEGF by short interfering RNA (siRNA) was used to explore the role of VEGF. High V(T) ventilation induced the increases of microvascular permeability, neutrophil influx, expressions of VEGF mRNA and VEGF, production of VEGF protein, positive staining of VEGF in epithelium, and apoptotic epithelial cell death. Lung injury induced by high V(T) ventilation was attenuated with the supply of hydroxyethyl starch and pharmacologic inhibition of VEGF expression by siRNA. We conclude that hydroxyethyl starch reduces high V(T) mechanical ventilation-induced lung injury and neutrophil infiltration through an inhibition of VEGF expression.

Biomarkers in acute lung injury: insights into the pathogenesis of acute lung injury

Studies of potential biomarkers of acute lung injury (ALI) have provided information relating to the pathophysiology of the mechanisms of lung injury and repair. The utility of biomarkers remains solely among research tools to investigate lung injury and repair mechanisms. Because of lack of sensitivity and specificity, they cannot be used in decision making in patients with ALI or acute respiratory distress syndrome. The authors reviewed known biomarkers in context of their major biologic activity. The continued interest in identifying and studying biomarkers is relevant, as it provides information regarding the mechanisms involved in lung injury and repair and how this may be helpful in identifying and designing future therapeutic targets and strategies and possibly identifying a sensitive and specific biomarker.

Exogenous administration of vascular endothelial growth factor prior to human respiratory syncytial virus a2 infection reduces pulmonary pathology in neonatal lambs and alters epithelial innate immune responses

Human respiratory syncytial virus (RSV) affects thousands of children every year. Vascular endothelial growth factor (VEGF) is a regulator of vasculogenesis, pulmonary maturation, and immunity. In order to test the extent to which VEGF may alter RSV infection, 4 groups of lambs received either human recombinant VEGF (rhVEGF) or phosphate-buffered saline (PBS) pretreatment followed by inoculation with human RSV strain A2 or sterile medium. Lambs in each group were sacrificed at 2, 4, and 6 days post infection. Expression of surfactant protein-A (SP-A), surfactant protein-D (SP-D), sheep β-defensin-1 (SBD-1), tumor necrosis factor α (TNFα), interleukin (IL)-6, IL-8, interferon β, and endogenous VEGF were measured to determine effect of rhVEGF pretreatment. RSV lambs pretreated with rhVEGF had reduced viral mRNA and decreased pulmonary pathology at day 6. Pretreatment with rhVEGF increased mRNA expression of SP-A, SBD-1, and TNFα, with alteration of expression in RSV lambs. Endogenous VEGF mRNA levels were increased at day 2 regardless of pretreatment. Pretreatment with rhVEGF increased pulmonary cellular proliferation in RSV lambs at day 4 post infection. Overall, these results suggest that pretreatment with rhVEGF protein may have therapeutic potential to decrease RSV viral load, decrease pulmonary lesion severity, and alter both epithelial innate immune responses and epithelial cell proliferation.

Lung exposure of titanium dioxide nanoparticles induces innate immune activation and long-lasting lymphocyte response in the Dark Agouti rat

Nanomaterial of titanium dioxide (TiO(2)) is manufactured in large-scale production plants, resulting in risks for accidental high exposures of humans. Inhalation of metal oxide nanoparticles in high doses may lead to both acute and long-standing adverse effects. By using the Dark Agouti (DA) rat, a strain disposed to develop chronic inflammation following exposure to immunoactivating adjuvants, we investigated local and systemic inflammatory responses after lung exposure of nanosized TiO(2) particles up to 90 days after intratracheal instillation. TiO(2) induced a transient response of proinflammatory and T-cell-activating cytokines (interleukin [IL]-1α, IL-1β, IL-6, cytokine-induced neutrophil chemoattractant [CINC]-1, granulocyte-macrophage colony-stimulating factor [GM-CSF], and IL-2) in airways 1-2 days after exposure, accompanied by an influx of eosinophils and neutrophils. Neutrophil numbers remained elevated for 30 days, whereas the eosinophils declined to baseline levels at Day 8, simultaneously with an increase of dendritic cells and natural killer (NK) cells. The innate immune activation was followed by a lymphocyte expansion that persisted throughout the 90-day study. Lymphocytes recruited to the lungs were predominantly CD4(+) helper T-cells, but we also demonstrated presence of CD8(+) T-cells, B-cells, and CD25(+) T-cells. In serum, we detected both an early cytokine expression at Days 1-2 (IL-2, IL-4, IL-6, CINC-1, IL-10, and interferon-gamma [IFN-γ] and a second response at Day 16 of tumor necrosis factor-alpha (TNF-α), indicating systemic late-phase effects in addition to the local response in airways. In summary, these data demonstrate a dynamic response to TiO(2) nanoparticles in the lungs of DA rats, beginning with an innate immune activation of eosinophils, neutrophils, dendritic cells, and NK cells, followed by a long-lasting activation of lymphocytes involved in adaptive immunity. The results have implications for the assessment of risks for adverse and persistent immune stimulation following nanoparticle exposures in sensitive populations.

Interstitial lung disease during chemotherapy combined with oxaliplatin and/or bevacizumab in advanced colorectal cancer patients

OBJECTIVE

Interstitial lung disease in patients with colorectal cancer during chemotherapy combined with bevacizumab is rare.

METHODS

We reviewed 104 colorectal cancer patients treated with standard chemotherapy with bevacizumab and examined the incidence of interstitial lung disease and its clinical features.

RESULTS

We identified interstitial lung disease in four patients (3.85%). All patients were male. The median age was 64.5 years. Three of four patients had a history of smoking; median smoking index was 40 pack-years. Except one patient who had asymptomatic pulmonary fibrosis, chest computed tomography before chemotherapy showed no fibrotic changes. Pulmonary function test before chemotherapy showed normal values. All patients had received median 10 cycles (range 10-15 cycles) of FOLFOX before the onset of interstitial lung disease. Interstitial lung disease developed during FOLFOX + bevacizumab in two patients and during FOLFIRI + bevacizumab in two patients. The initial symptom of interstitial lung disease was fever in all patients. The median duration from the last chemotherapy to the onset of interstitial lung disease was 3.5 days (range 2-8 days). Three of four patients showed Grade 3 or more severity of interstitial lung disease according to Common Terminology Criteria for Adverse Events v3.0. High-dose steroid therapy was effective in all patients.

CONCLUSIONS

Interstitial lung disease induced by standard chemotherapy with bevacizumab is rare, but rapidly progressed and were severe in our experience.

Sorafenib-induced interstitial pneumonitis in a patient with hepatocellular carcinoma: a case report

Sorafenib is an oral multikinase inhibitor that has shown a survival benefit in patients with advanced hepatocellular carcinoma, and is considered to be generally safe. We treated a patient with interstitial lung disease that was associated with sorafenib therapy for the treatment of advanced hepatocellular carcinoma. A 74-year-old man with hepatitis-C-virus-related hepatocellular carcinoma was treated with sorafenib. After 8 days of sorafenib administration, he received radiation therapy for an intrahepatic tumor located in segment eight. On the 24th day of sorafenib treatment, the patient developed acute interstitial pneumonitis that rapidly improved after the discontinuation of sorafenib and treatment with high-dose steroids. This case alerts physicians to the possibility of sorafenib-induced interstitial lung disease.

VEGF in the lung: a role for novel isoforms

Vascular endothelial cell growth factor (VEGF) is a potent mitogen and permogen that increases in the plasma and decreases in the alveolar space in respiratory diseases such as acute respiratory distress syndrome (ARDS). This observation has led to controversy over the role of this potent molecule in lung physiology and disease. We hypothesized that some of the VEGF previously detected in normal lung may be of the anti-angiogenic family (VEGF(xxx)b) with significant potential effects on VEGF bioactivity. VEGF(xxx)b protein expression was assessed by indirect immunohistochemistry in normal and ARDS tissue. Expression of VEGF(xxx)b was also detected by immunoblotting in normal lung tissue, primary human alveolar type II (ATII) cells, and bronchoalveolar lavage (BAL) fluid in normal subjects and by ELISA in normal, "at risk," and ARDS subjects. The effect of VEGF(165) and VEGF(165)b on both human primary endothelial cells and alveolar epithelial cell proliferation was assessed by [(3)H]thymidine uptake. We found that VEGF(165)b was widely expressed in normal healthy lung tissue but is reduced in ARDS lung. VEGF(121)b and VEGF(165)b were present in whole lung, BAL, and ATII lysate. The proliferative effect of VEGF(165) on both human primary endothelial cells and human alveolar epithelial cells was significantly inhibited by VEGF(165)b (P < 0.01). These data demonstrate that the novel VEGF(xxx)b family members are expressed in normal lung and are reduced in ARDS. A specific functional effect on primary human endothelial and alveolar epithelial cells has also been shown. These data suggest that the VEGF(xxx)b family may have a role in repair after lung injury.

Functions of type II pneumocyte-derived vascular endothelial growth factor in alveolar structure, acute inflammation, and vascular permeability

Vascular endothelial growth factor-A (VEGF) is a potent regulator of vascular permeability, inflammatory response, and cell survival in the lung. To explore the functions of VEGF produced locally in type II pneumocytes, we generated mice with a conditional deletion of VEGF-A using Cre recombinase driven by the human surfactant protein C (SPC) promoter. In 7- to 10-week-old VEGF-knockout (SPC-VEGF-KO) mice, lung histology and physiology were essentially normal, except for higher dynamic lung compliance and lower pulmonary vascular permeability. Emphysema was seen in 28- to 32-week-old animals. To investigate the role of type II pneumocyte-derived VEGF in acute lung injury, we challenged 7- to 10-week-old SPC-VEGF-KO mice and their wild-type littermates with intestinal ischemia-reperfusion. Bronchoalveolar lavage fluid total cell count, pulmonary permeability, and lung injury score were significantly attenuated, and total lung VEGF levels were significantly lower in SPC-VEGF-KO mice compared with wild-type controls. In SPC-VEGF-KO mice, activated caspase 3-positive type II epithelial cells were increased after intestinal ischemia-reperfusion, even though there was no significant difference in the total number of cells positive for terminal deoxynucleotidyl transferase dUTP nick-end labeling. We conclude that VEGF in type II cells helps protect alveolar epithelial cells from caspase-dependent apoptosis. However, VEGF produced from type II cells may contribute to increased vascular permeability during acute lung injury.

Vascular endothelial growth factor receptor and coreceptor expression in human acute respiratory distress syndrome

BACKGROUND

Acute respiratory distress syndrome (ARDS) is characterized by the development of noncardiogenic pulmonary edema, which has been related to the bioactivity of vascular endothelial growth factor (VEGF). Vascular endothelial growth factor receptors and coreceptors regulate this bioactivity. We hypothesized VEGF receptors 1 and 2 (VEGFR1, VEGFR2) and coreceptor neuropilin-1 (NRP-1) would be expressed in human lung tissue with a significant change in expression in ARDS lung.

METHODS

Archival "normal" (no lung pathology and non-ARDS), "early" (within 48 hours), and "later" (after day 7) ARDS lung-tissue sections (n = 5) were immunostained for VEGFR1, VEGFR2, and NRP-1 from human subjects (n = 4). Staining was assessed densitometrically using Histometrix software.

RESULTS

VEGFR1, VEGFR2, and NRP-1 were expressed on both sides of the alveolar-capillary membrane in both normal and ARDS human lung tissue. In later ARDS, there was a significant up-regulation of VEGFR1 and VEGFR2 versus normal and early ARDS (P < .0001). Neuropilin-1 was down-regulated in early ARDS versus normal lung (P < .05), with normalization in later ARDS (P < .001).

CONCLUSION

Differential temporal VEGFR1, VEGFR2, and NRP-1 up-regulation occurs in human ARDS, providing evidence of further functional regulation of VEGF bioactivity via VEGFR2 consistent with a protective role for VEGF in lung injury recovery. The mechanisms behind these observations remain to be clarified.

Vascular Endothelial Growth Factor (VEGF) isoform expression and activity in human and murine lung injury

BACKGROUND

The properties of vascular endothelial growth factor (VEGF) as a potent vascular permogen and mitogen have led to investigation of its potential role in lung injury. Alternate spliced VEGF transcript generates several isoforms with potentially differing functions. The purpose of this study was to determine VEGF isoform expression and source in normal and ARDS subjects and investigate the expression and regulation of VEGF isoforms by human alveolar type 2 (ATII) cells.

METHODS

VEGF protein expression was assessed immunohistochemically in archival normal and ARDS human lung tissue. VEGF isoform mRNA expression was assessed in human and murine lung tissue. Purified ATII cells were cultured with proinflammatory cytokines prior to RNA extraction/cell supernatant sampling/proliferation assay.

MEASUREMENTS AND MAIN RESULTS

VEGF was expressed on alveolar epithelium, vascular endothelium and alveolar macrophages in normal and ARDS human lung tissue. Increases in VEGF expression were detected in later ARDS in comparison to both normal subjects and early ARDS (p < 0.001). VEGF121, VEGF165 and VEGF189 isoform mRNA expression increased in later ARDS (p < 0.05). The ratio of soluble to cell-associated isoforms was lower in early ARDS than normal subjects and later ARDS and also in murine lung injury. ATII cells constitutionally produced VEGF165 and VEGF121 protein which was increased by LPS (p < 0.05). VEGF165 upregulated ATII cell proliferation (p < 0.001) that was inhibited by soluble VEGF receptor 1 (sflt) (p < 0.05).

CONCLUSION

These data demonstrate that changes in VEGF isoform expression occur in ARDS which may be related to their production by and mitogenic effect on ATII cells; with potentially significant clinical consequences.

The pathogenetic and prognostic value of biologic markers in acute lung injury

Over the past 2 decades, measurement of biomarkers in both the airspaces and plasma early in the course of acute lung injury has provided new insights into the mechanisms of lung injury. In addition, biologic markers of cell-specific injury, acute inflammation, and altered coagulation correlate with mortality from acute lung injury in several single center studies as well as in multicenter clinical trials. To date, biomarkers have been measured largely for research purposes. However, with improved understanding of their role in the pathogenesis of acute lung injury, biomarkers may play an important role in early detection of lung injury, risk stratification for clinical trials, and, ultimately, tailoring specific therapies to individual patients. This article provides a review of biologic markers in acute lung injury, with an emphasis on recent analysis of results from multicenter clinical trials.

Minimally invasive colon resection is associated with a transient increase in plasma sVEGFR1 levels and a decrease in sVEGFR2 levels during the early postoperative period

INTRODUCTION

Plasma vascular endothelial growth factor (VEGF) levels are elevated for 2-4 weeks after minimally invasive colorectal resection (MICR). VEGF induces wound and tumor angiogenesis by binding to endothelial cell (EC)-bound VEGF-receptor 1 (VEGFR1) and VEGFR2. Soluble receptors (sVEGFR1, sVEGFR2) sequester VEGF in the blood and decrease VEGF's proangiogenic effect. The importance of the MICR-related VEGF changes depends on the effect of surgical procedures on sVEGFR1 and sVEGFR2; this study assessed levels of these proteins after MICR for benign indications.

METHODS

Blood samples were taken (n=39) preoperatively (preop) and on postoperative days (POD) 1 and 3; in most cases a fourth sample was drawn between POD 7 and 30. sVEGFR1 and sVEGFR2 levels were measured via enzyme-linked immunosorbent assay (ELISA), which detects free and VEGF bound soluble receptor. Late samples were bundled into POD 7-13 and POD 14-30 time points. Results are reported as mean and standard deviation. The data was assessed with paired-samples t-test.

RESULTS

Preop, mean plasma sVEGFR2 level (9,203.7+/-1,934.3 pg/ml) was significantly higher than the sVEGFR1 value (132.5+/-126.2 pg/ml). sVEGFR2 levels were significantly lower on POD 1 (6,957.8+/-1,947.7 pg/ml,) and POD 3 (7,085.6+/-2,000.2 pg/ml), whereas sVEGFR1 levels were significantly higher on POD 1 (220.0+/-132.8 pg/ml) and POD 3 (182.7+/-102.1 pg/ml) versus preop results. No differences were found on POD 7-13 or 14-30.

CONCLUSIONS

sVEGFR2 values decreased and sVEGFR1 levels increased early after MICR; due to its much higher baseline, the sVEGFR2 changes dominate. The net result is less VEGF bound to soluble receptor and more free plasma VEGF.

Differential cytokine secretion and early treatment response in patients with pulmonary tuberculosis

Biomarkers for treatment response would facilitate the testing of urgently needed new anti-tuberculous drugs. The present study investigated the profiles of 30 proinflammatory, anti-inflammatory and angiogenic factors [epidermal growth factor, eotaxin, fractalkine, granulocyte colony-stimulating factor, granulocyte-macrophage colony-stimulating factor, interleukin (IL)-1alpha, IL-1beta, IL-1ra, IL-2, IL-4, IL-5, IL-6, IL-7, IL-8, IL-10, IL-12p40, IL-12p70, IL-13, IL-15, IL-17, interferon-gamma, interferon-inducible protein-10, Krebs von den Lungen-6, monocyte chemotactic protein-1, macrophage inflammatory protein (MIP)-1alpha, MIP-1beta, sCD40L, transforming growth factor-alpha, tumour necrosis factor-alpha and vascular endothelial growth factor] in the plasma of 12 healthy tuberculin skin test-positive community controls and 20 human immunodeficiency virus-negative patients with active tuberculosis (TB) and identified potential biomarkers for early treatment response. We showed differences in the level of circulating cytokines between healthy controls and TB patients, but also between fast responders and slow responders to anti-tuberculosis treatment. The general discriminant analysis based on pre-treatment and week 1 measurements identified 10 sets of three-variable models that could classify fast and slow responders with up to 83% accuracy. Overall, this study shows the potential of cytokines as indicators of anti-tuberculosis treatment response.