Increased serum levels of vascular endothelial growth factor in patients with inflammatory bowel disease

Vascular endothelial growth factor secretion from mesenteric adipose tissue and from creeping fat in Crohn's disease

BACKGROUND

Creeping fat represents a characteristic feature of Crohn's disease (CD), and adipose tissue secretes adipocytokines and chemokines/growth factors such as vascular endothelial growth factor (VEGF). Because VEGF serum levels and mucosal VEGF expression is elevated in CD patients, the aim of the present paper was to investigate creeping fat-derived VEGF secretion in CD.

MATERIAL AND METHODS

Adipose tissue was obtained from creeping fat of 10 patients with CD. Mesenteric adipose tissue was resected from 13 patients with colon cancer (CC) and from seven patients with diverticulitis (DIV). Three fat tissue specimens per well, and several wells (6-8) per patient were incubated ex vivo for 24 h. The release of VEGF into the supernatant was measured by ELISA.

RESULTS

There was stable VEGF secretion from mesenteric adipose tissue of patients with CC or DIV and from creeping fat of patients with CD. Whereas the VEGF secretion rate was not different between patients with CD (465 +/- 98 pg/g fat per 24 h) and CC (399 +/- 48 pg/g fat per 24 h), VEGF secretion was significantly reduced in patients suffering from DIV (115 +/- 41 pg/g fat per 24 h; P < 0.0001 and P = 0.001, respectively). The CD patients treated with steroids had significantly lower VEGF secretion rates (294 +/- 42 pg/g fat per 24 h) than CD patients not receiving steroids (607 +/- 105 pg/g fat per 24 h; P = 0.001).

CONCLUSIONS

Creeping fat is an important source of VEGF secretion. The characteristics of the inflammatory changes in CD might be due to the lack of VEGF downregulation that is seen in DIV.

Increased serum level of vascular endothelial growth factor in Mycobacterium avium complex infection

OBJECTIVE

Pulmonary infection caused by Mycobacterium avium complex (MAC) is one of the granulomatous diseases which are associated with the expression of vascular endothelial growth factor (VEGF). The aim of the present study was to clarify the association of VEGF with the pathogenesis of MAC infection.

METHODOLOGY

The serum VEGF levels in 46 patients with pulmonary MAC infection were compared with those in 16 normal control subjects. Pulmonary lesions were evaluated using chest CT. In 20 patients, after treatment, serum VEGF levels were measured and chest CT performed again to evaluate pulmonary response to treatment.

RESULTS

Infected patients had higher serum VEGF levels than controls (435.2 +/- 29.1 vs. 167.0 +/- 10.6 pg/mL, P < 0.0001), and serum VEGF level correlated with the extent of disease. The serum VEGF levels in 14 patients who underwent treatment and exhibited an improvement in their pulmonary lesions decreased significantly compared with the results pretreatment (509.0 +/- 60.7 vs. 303.6 +/- 65.3 pg/mL, P = 0.0092). In infected patients, alveolar macrophages, epithelioid cells and multinucleated giant cells exhibited VEGF overexpression on immunohistochemical staining.

CONCLUSIONS

This study suggests that VEGF may be associated with the pathogenesis of pulmonary MAC infection. Additionally, serum VEGF levels may be a useful surrogate marker for evaluating the extent of disease and of the response to treatment.

Role of angiogenesis in inflammatory bowel disease

Several studies have shown alterations in vascular anatomy and physiology in inflammatory bowel disease (IBD). These findings, together with the observed upregulation of the mediators of angiogenesis in IBD patients, suggest that angiogenesis possibly contributes to the initiation and perpetuation of IBD. There is considerable evidence of an interrelationship between the mechanisms of angiogenesis and chronic inflammation in IBD. The increased expression of endothelial junction adhesion molecules found in IBD patients indicates the presence of active angiogenesis. Evidence that angiogenesis is involved in IBD was also obtained from animal models of colitis, most notably from studies of angiogenesis inhibition. Serum levels of vascular endothelial growth factor (VEGF) correlate with disease activity in human IBD and fall with the use of steroids, thalidomide, or infliximab. Pharmacological inhibition of angiogenesis, therefore, has the potential to be a therapeutic strategy in IBD. This review outlines the evidence that the rate of angiogenesis is increased in the inflamed intestine in IBD and proposes lines for future research in this field.

A case-control study of bronchial asthma associated with ulcerative colitis: role of airway microvascular permeability

BACKGROUND

Recent attention has been devoted to the respiratory manifestations that may be associated with diseases of distant organs. The most prevalent and distinctive pattern of respiratory involvement in ulcerative colitis (UC) is airway inflammation.

OBJECTIVE

This study was designed to examine the contribution of airway microvascular permeability to the pathophysiological association of asthma with UC.

METHODS

Sputum induction and methacholine provocation test were performed in 27 asthmatic patients (15 without UC and 12 with UC), nine patients with UC and 15 normal controls. Inflammatory indexes, vascular endothelial growth factor (VEGF) levels in induced sputum, airway vascular permeability index and exhaled nitric oxide (NO) levels were examined in all subjects.

RESULTS

The percentage of eosinophils and concentration of eosinophil cationic protein in induced sputum were similar in all four groups. Though exhaled NO levels were significantly higher in asthmatics with or without UC than in normal controls or UC patients, these levels were comparable in asthmatics with and without UC. VEGF levels in induced sputum and airway vascular permeability index were significantly higher in asthmatics without UC (VEGF: 1920 (990) pg/mL; airway vascular permeability index: 0.018 (0.008)) and asthmatics with UC (6570 (1000) pg/mL; 0.040 (0.006)) than in normal controls (950 (700) pg/mL; 0.009 (0.003)), whose levels were comparable to those of UC patients (900 (600) pg/mL; 0.011 (0.003)). In particular, these parameters were markedly increased in asthmatics with UC than in asthmatics without UC. VEGF level was significantly correlated with airway vascular permeability index in asthmatics with UC. Moreover, VEGF level and airway vascular permeability index was inversely correlated with degree of airway obstruction and airway hyper-reactivity to methacholine in these asthmatics.

CONCLUSION

Airway microvascular hyper-permeability induced by VEGF may have a profound effect on airway function and can explain the heightened airway hyper-responsiveness characteristic of asthma associated with UC.

Potential role of soluble angiopoietin-2 and Tie-2 in patients with inflammatory bowel disease

BACKGROUND

Angiogenesis has been suggested to play an important role in inflammatory bowel disease (IBD). The aim of the study was to evaluate the serum markers of angiogenesis angiopoietin-2 (Ang-2) and soluble angiopoietin receptor Tie-2 in patients with ulcerative colitis (UC) and Crohn's disease (CD).

MATERIALS AND METHODS

Serum Ang-2 and Tie-2 serum levels were measured in 160 IBD patients (79 UC and 81 CD) and in 80 matched healthy controls using commercially available enzyme-linked immunosorbent assays. Serum Ang-2 and Tie-2 levels were correlated with the disease activity, as well as the type, localization and treatment of the disease.

RESULTS

Median serum Ang-2 and Tie-2 levels were significantly higher in both the UC patients and the CD patients compared with the healthy controls (P < 0.05 and P < 0.001, respectively). The IBD patients with early disease (diagnosis < 2 years) had significantly higher (P = 0.04) median serum Ang-2 levels but significantly lower (P = 0.02) median serum Tie-2 levels as compared with IBD patients with late disease (diagnosis > 2 years). The CD patients with active disease had significantly higher levels of Ang-2 compared with non-active disease (P = 0.02). Serum levels of both Ang-2 and Tie-2 were not correlated with laboratory markers such as ESR, CRP, white blood cell count, platelet count and albumin.

CONCLUSIONS

Serum Ang-2 and Tie-2 levels are elevated in patients with IBD. These markers may mediate angiogenesis and vascular permeability in the mucosa of patients with IBD.

Role of tumor necrosis factor receptors in an animal model of acute colitis

TNF-alpha is known to play an important role in inflammatory bowel disease (IBD); however, the pathophysiological role of its receptors is still under study. Acute colitis was induced in rats by intracolonic administration of trinitrobenzene sulfonic acid (TNBS). Control rats received the ethanol vehicle. Rats were sacrificed 72 h later and samples of tissue and fluids were collected. There was a significant increase in the protein levels of sTNF-alpha, sTNFRI, and sTNFRII in the peritoneal fluid (PF) of experimental rats. TNF-alpha, TNFRI, and TNFRII mRNA expression was increased significantly in the colon of experimental animals compared to controls. TRAF3 and TRAF5 expression was also significantly higher, as was that of the adhesion molecules ICAM-1 and E-selectin. The increased expression of TNF-alpha, TNFRs, and the associated signaling factors in the colon of this rat model of IBD provides further evidence for their involvement in the promotion of inflammation and tissue damage. In addition, increased levels of sTNFRs in the PF of experimental rats--particularly sTNFRII--may be involved in the development of colitis by serving as a reservoir of TNF-alpha, and thus provide a novel therapeutic target for IBD.

Review article: angiogenesis soluble factors as liver disease markers

Angiogenesis is the formation of new blood vessels from pre-existing ones; it has been studied at the molecular level in different pathologies and is currently considered a promising novel therapeutic target in cancer. Recently, the use of angiogenesis soluble factors as markers of tumour growth has been investigated. The knowledge gained has led to test their use as therapeutic agents. Additionally, angiogenesis soluble factors could be used for the follow-up of pathologies that currently require monitoring with invasive techniques, like chronic viral hepatitis or renal and haematological diseases. The different factors have been described in multiple studies. In some cases, such as hepatocellular carcinoma, a potential use as prognostic markers has been suggested.

Vascular endothelial growth factor expression and microvessel parameters of colonic mucosa correlate with sensitivity to steroid in patients with ulcerative colitis

OBJECTIVE

Vascular endothelial growth factor (VEGF) expression and microvessel parameters have not yet been quantified in the colonic mucosa of ulcerative colitis (UC). The aim of this study was to correlate the parameters with clinical responsiveness to steroid therapy.

MATERIAL AND METHODS

Colorectal biopsy specimens from 39 UC patients with high sensitivity to steroid (H-UC), 9 UC patients with low sensitivity to steroid (L-UC) and 6 normal controls (NC) were examined.

METHODS

Tissue sections were immunostained with anti-VEGF antibody for number of inflammatory cells (/mm(2)), VEGF-positive cell (/mm(2)) and VEGF-positive ratio (%), and with CD34 for microvessel counts (/mm(2)) and the mean microvessel diameter (microm).

RESULTS

The H-UC group had a significantly larger total cell count (10,048+/-2751, p<0.0001) or VEGF-positive cells (2363+/-707, p<0.0001) than the NC group (7235+/-2088 or 1537+/-297, respectively) with no difference in VEGF-positive ratio (24.3+/-6.9 for H-UC versus 22.7+/-6.9 for NC). The L-UC group had a significantly lower VEGF-positive cell count (1420+/-701, p<0.0005) or VEGF-positive ratio (11.6+/-5.5, p<0.0005) than the H-UC group, whereas microvessel counts were almost constant regardless of the subject groups (345+/-7 0 for NC versus 346+/-99 for H-UC versus 349+/-114 for L-UC). Significant increases in microvessel diameter were seen when comparing NC (6.68+/-0.60) with H-UC (7.83+/-1.09, p<0.0001) and H-UC with L-UC (9.05+/-1.70, p<0.03). Out of the five parameters, VEGF-positive ratio and microvessel diameter had a predictive value for L-UC with an 88.9% sensitivity and 88.9% specificity.

CONCLUSIONS

L-UC was characterized either as VEGF underexpression or enlarged microvessel. The disruption of the healing process or disturbance of microcirculation may be involved in low sensitivity to steroid therapy in UC.

Effect of granulocyte and monocyte adsorption apheresis on urinary albumin excretion and plasma endothelin-1 concentration in patients with active ulcerative colitis

BACKGROUND/AIM

Increases in microalbuminuria and endothelin (ET-1) are involved in the development of ulcerative colitis (UC) and in its progress. Because granulocyte and monocyte adsorption apheresis has proven to be useful in the treatment of UC, we examined whether urinary albumin excretion and plasma ET-1 concentrations are altered and whether granulocyte and monocyte adsorption apheresis affects the concentrations of these two factors in patients with active UC.

METHODS

Twenty patients with active UC and 20 age-matched healthy volunteers (our hospital staffs) were included in this study. UC patients were randomly divided into two treatment groups: a granulocyte and monocyte adsorption treatment group (n = 10) and a conventional treatment group (n = 10). The urine albumin/creatinine ratio, plasma ET-1 concentration and tumor necrosis factor (TNF)-alpha were determined before and after treatment and compared between 2 treatment groups. The 10 adsorption treatment patients underwent 5 consecutive weekly apheresis sessions, each of 60 min duration at a flow rate of 30 ml/min.

RESULTS

The urine albumin/creatinine ratio in UC patients (6.4 +/- 2.2 mg/mmol) were higher than that in healthy subjects (1.0 +/- 0.7 mg/mmol, p < 0.01). In addition, the plasma ET-1 level in UC patients (3.5 +/-1.5 pg/ml) was higher than that in healthy subjects (0.8 +/- 0.4 pg/ml, p < 0.01). Plasma TNF-alpha was detected in UC patients (18.8 +/- 8.4 pg/ml), but not in healthy subjects. The urine albumin/creatinine ratio was highly correlated with the plasma ET-1 level (r = 0.62; p < 0.01) and plasma TNF-a level (r = 0.66, p < 0.01). Granulocyte and monocyte adsorption apheresis reduced the urine albumin/ creatinine ratio from 6.6 +/- 2.4 to 1.8 +/- 0.6 mg/mmol (p < 0.01), reduced the plasma ET-1 level from 3.7 +/- 1.6 to 1.4 +/- 0.6 pg/ml (p < 0.05) and reduced the plasma TNF-alpha from 19.2 +/- 8.6 to 3.8 +/- 1.2 pg/ml (p < 0.01). Conventional treatment did not affect these factors.

CONCLUSION

Our data suggest that increases in the urine albumin/creatinine ratio, ET-1 and TNF-alpha play an important role in active UC and that granulocyte and monocyte adsorption apheresis is effective in ameliorating such increases.

Serum angiogenin in inflammatory bowel disease

Angiogenesis-promoting cytokines have been suggested to play an important role in inflammatory bowel disease (IBD) since they promote inflammation by increasing vascular permeability and mediate tissue repair by activating fibroblasts. The aim of the present study was to evaluate the serum levels of angiogenin, a potent angiogenic factor, in patients with ulcerative colitis (UC) and Crohn's disease (CD). Angiogenin serum levels were measured in 154 IBD patients (78 UC and 76 CD), in 18 cases with other causes of intestinal inflammation, and in 84 matched healthy controls using a commercially available enzyme-linked immunosorbent assay. Angiogenin levels were assessed in terms of disease activity, type, localization, and treatment. Mean (+/-SD) serum angiogenin levels were 526.5+/-224.1 ng/ml in UC patients, 508.8+/-228.5 ng/ml in CD patients, 394.6+/-137.6 ng/ml in healthy controls, and 448.1+/-167.8 ng/ml in patients with non-IBD intestinal inflammation. A statistically significant difference among the mean levels of angiogenin in the four groups was found (P = 0.0003). IBD patients with early disease had a significantly lower mean serum angiogenin compared with patients with late disease (P = 0.03). No significant association between angiogenin levels and disease activity, localization, disease type, or treatment was found. Serum angiogenin is elevated in patients with IBD. The increased serum angiogenin suggests that angiogenin may mediate angiogenesis and vascular permeability in the mucosa of patients with IBD.

Serum bFGF and VEGF correlate respectively with bowel wall thickness and intramural blood flow in Crohn's disease

Serum levels of basic fibroblast growth factor (bFGF) and vascular endothelial growth factor (VEGF)--two factors known to promote tissue repair, fibroblast proliferation, and angiogenesis--were measured in Crohn's disease patients and correlated with bowel wall thickness (BWT), measured by conventional grey scale ultrasonography, and with the ileal intramural vessel flow, measured by contrast-enhanced color Doppler imaging. Serum samples were obtained from 25 patients with active Crohn's disease and 22 healthy volunteers, all sex- and age-matched. Serum bFGF and VEGF levels were measured by ELISA assay. All the patients were examined with conventional transabdominal bowel sonography. Color Doppler of the intramural enteric vessels was then performed after the intravenous injection of Levovist, a galactose-based sonographic contrast agent. In Crohn's disease patients, serum bFGF and VEGF were significantly higher compared with healthy volunteers. A positive correlation between serum bFGF and BWT and between serum VEGF and color Doppler signal intensity was found. The raised serum bFGF levels in Crohn's disease patients with intestinal strictures compared with patients with other phenotypes (fistulizing, inflammatory), together with the correlation observed between serum bFGF and BWT, suggests a possible involvement of bFGF in the process of transmural fibrogenesis in Crohn's disease. The higher levels of VEGF in those patients with increased intramural blood flow suggests that VEGF may be considered a marker of angiogenesis in this condition.

Infliximab downregulates basic fibroblast growth factor and vascular endothelial growth factor in Crohn's disease patients

BACKGROUND

The use of infliximab in the treatment of Crohn's disease patients with symptomatic stenosis is controversial.

AIM

To explore the influence of this agent on intestinal fibrogenesis by measuring in infliximab-treated Crohn's disease patients the serum levels of basic fibroblast growth factor and vascular endothelial growth factor, two factors known to be involved in the process of intestinal wound healing and fibrosis in this condition.

METHODS

Serum levels of basic fibroblast growth factor and vascular endothelial growth factor were determined by enzyme-linked immunosorbent assay in 22 patients with steroid refractory or fistulizing Crohn's disease before, during (2 weeks) and after 12 weeks of treatment with infliximab, administered at week 0, 2 and 6 in a dose of 5 mg/kg.

RESULTS

A substantial improvement in 19 of the 22 Crohn's disease patients was accompanied by a rapid and durable reduction in basic fibroblast growth factor and vascular endothelial growth factor serum levels.

CONCLUSIONS

The action of infliximab in reducing serum basic fibroblast growth factor and vascular endothelial growth factor would seem to suggest a role of this agent in down-regulating the process of intestinal fibrogenesis in Crohn's disease.

Increased vascular endothelial growth factor production in fibroblasts isolated from strictures in patients with Crohn's disease

BACKGROUND

Vascular endothelial growth factor (VEGF) is a potent angiogenic factor that is implicated in early wound healing and fibrosis. Fibroblasts may initiate stricture formation in Crohn's disease through overexpression of VEGF. The aim of this study was to examine VEGF expression and regulation in fibroblasts isolated from patients with Crohn's disease.

METHODS

Fibroblasts were isolated by a primary explant technique from serosal biopsies of non-strictured and strictured segments of bowel from eight patients undergoing resection for Crohn's disease, and normal colon from six patients undergoing resection for benign and malignant colorectal disease. Fibroblasts were cultured with transforming growth factor (TGF) beta and corticosteroids. After 24 h the culture supernatant was collected for VEGF assay by enzyme-linked immunosorbent assay.

RESULTS

VEGF production was significantly higher in fibroblasts isolated from strictures (mean(s.e.m.) 1980(260) pg/ml) than from non-strictured segments (1116(165) pg/ml) in patients with Crohn's disease or control fibroblasts (898(93) pg/ml). TGF-beta increased VEGF production in normal and non-strictured Crohn's fibroblasts. Corticosteroids suppressed unstimulated VEGF production in all groups.

CONCLUSION

Enhanced serosal fibroblast VEGF production might play a role in initiating stricture formation in Crohn's disease. VEGF production in serosal fibroblasts is sensitive to stimulation with TGF-beta. Corticosteroids may reduce stricturing through suppression of VEGF.

The Potential Contributions of Chronic Inflammation to Lung Carcinogenesis

A number of lines of evidence suggests that chronic inflammation contributes to the process of carcinogenesis. In this article, this theme is explored with particular emphasis on the involvement of inflammation in the development of lung cancer. A number of molecular pathways activated in chronic inflammation may contribute to lung carcinogenesis. The challenge is to conceptualize a cohesive picture of this complex biology that allows for effective pharmaceutical intervention. Initial therapeutic efforts involve strategies to block single pathways, such as with cyclooxygenase (COX) activity. However, the more that is learned about the consequences of COX activity, the more evident are the relationships of this enzyme to other classes of regulatory molecules such as the potent nuclear factor-kB. In light of this emerging picture, more global intervention strategies, such as with drug combinations, may be essential for success. Further basic study is essential to sort out possible molecular relationships and to permit elucidation of the most critical regulatory circuits. Given the complexity of these molecular interactions, well-designed clinical trials that specifically evaluate the precise effects of particular antiinflammatory drugs on lung carcinogenesis will also be critical to sort out the complexity and to validate successful approaches to arresting lung carcinogenesis.

Effects of in vivo treatment with interleukins 1beta and 6 on rat mesenteric vascular bed reactivity

1. Inflammatory bowel disease (IBD) is a condition that involves proinflammatory cytokines such as interleukins 1beta and 6 (ILs). In this disease, it has been shown that an abnormal microcirculatory system is implicated. 2. Therefore, the effects of in vivo treatment for three days with interleukins 1beta and 6 were investigated on rat isolated mesenteric vascular bed (MVB). 3. A significant concentration-dependent increase in vascular response to noradrenaline (NA) was found, with a significant difference in Emax between control (93.01 +/- 16.78 mmHg) and treated preparations (137.91 +/- 5.20 mmHg). Endothelin-1(ET-1) induced a significantly greater increase of perfusion pressure in treated rats in comparison with control rats at the highest concentration used (0.1 microm). 4. The concentration-dependent decrease of perfusion pressure induced by acetylcholine (ACh) in MVB precontracted with NA was significantly reduced in specimens from treated rats in comparison with control rats, with a significant difference in Emax between control and treated preparations. 5. Perivascular nerve stimulation (PNS) evoked contractions with no difference between treatments. Similarly, no difference in relaxant effect was found after PNS in specimens precontracted with NA, in the presence of guanethidine. 6. These findings indicate that the precocious inflammation acts only at postsynaptic level, facilitating vascular contraction. These data seem to support the hypothesis that vascular dysfunction caused by overproduction of ILs may contribute, among other immunological factors, to vasculitis in IBD that leads to intestinal ischaemia through vasoconstriction.

Thalidomide in gastrointestinal disorders

Thalidomide was originally marketed as a sedative, but was removed from the market in 1961 after it was associated with an epidemic of severe birth defects. Subsequently, it has been shown to have therapeutic efficacy in a number of the gastrointestinal tract conditions characterised by immune dysregulation. The exact mechanism of the immunosuppressive effects of thalidomide is unknown; proposed mechanisms include inhibition of tumour necrosis factor alpha release and inhibition of angiogenesis. In chronic graft versus host disease, use of high dose thalidomide (1200 mg/day) may bring about a response in 20% of patients with refractory disease. Thalidomide 200 mg/day helps eradicate ulcers in 50% of patients with HIV-associated oral aphthous ulceration. In Behçet's disease, thalidomide 100 to 300 mg/day can decrease the number of mucocutaneous ulcers, although full remission occurs in less than 20% of patients. In Crohn's disease, thalidomide 50 to 300 mg/day may decrease the severity of mucosal disease and prompt closure of fistulae. Patients to be placed on thalidomide therapy must practice either abstinence or strict birth control; women must undergo regular pregnancy testing and utilise 2 forms of contraception. Other adverse effects include sedation (present in nearly all patients), symptomatic neuropathy (present in approximately 20%), and skin rashes. Given the potential toxicity, thalidomide use should generally be limited to clinical protocols with institutional review board oversight.

VEGF, basic-FGF, and TGF-beta in Crohn's disease and ulcerative colitis: a novel mechanism of chronic intestinal inflammation

OBJECTIVE

Inflammatory bowel disease (IBD), the precise etiology of which remains unknown, is comprised of two forms of chronic intestinal inflammation; ulcerative colitis (UC) and Crohn's disease (CD). Recent evidence increasingly suggests that IBD is the result of dysfunctional immunoregulation manifested by inappropriate production of mucosal cytokines. An abnormal microcirculatory system has also been implicated in its pathogenesis. To elucidate the mechanism of ischemic change in IBD, we assesse serum concentration levels of vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (b-FGF), and plasma level of endothelin-1 (ET-1). We also investigated the expression of VEGF, b-FGF, and transforming growth factor-beta1,2,3 (TGF-beta1,2,3) in tissue by immunostaining.

METHODS

Blood samples were obtained from 11 patients with UC, 11 patients with CD, and 10 patients as controls. Paraffin-embedded samples were used for an immunohistochemical study.

RESULTS

The concentration levels (in picograms per milliliter) were as follows: for ET-1, UC: 127+/-47.0, CD: 167.3+/-35.1, and controls (asthma: 38.5+/-23.8, p < 0.01; diverticulitis: 40.5+/-25.6, p < 0.01), for b-FGF, UC: 9.2+/-1.9, CD: 9.1+/-1.5, and controls (asthma: 5.0+/-0, p < 0.01; diverticulitis: 5.0+/-0, p < 0.01), for VEGF, UC: 659.8+/-181.0, CD: 740.0+/-182.3, and controls (asthma: 193.7+/-58.7, p < 0.01; diverticulitis: 199.6+/-59.7, p < 0.01). The levels of VEGF and b-FGF were significantly higher in active IBD than those in the controls. There was a significant positive correlation among the serum levels of VEGF and b-FGF and the plasma level of ET-1; that is, elevated VEGF, b-FGF, and ET-1 levels correlated well with each other. Immunohistochemical studies showed increased venula in the submucosa and lamina propria. Overexpression of VEGF and b-FGF in endothelial cells was revealed and TGF-beta2 and TGF-beta3 were found in inflammatory cells of active IBD, but no change was observed around the vessels in the controls.

CONCLUSIONS

It is suggested that the reciprocal reaction of these cytokines may contribute to angiogenesis in IBD b inducing intestinal ischemia through vasoconstriction.

Increased serum level of vascular endothelial growth factor in pulmonary tuberculosis

Pulmonary tuberculosis, one of the granulomatous diseases, has few serological markers for its activity. Recently, an increased serum level of vascular endothelial growth factor (VEGF) was detected in patients with Crohn's disease, also a granulomatous disease. We hypothesized that VEGF might be associated with the pathogenesis of pulmonary tuberculosis. We investigated the serum level of VEGF in 43 patients with active pulmonary tuberculosis, 29 patients with old tuberculosis, and 25 patients with acute bronchitis. We were able to examine the serum VEGF levels every 3 mo for a period of 6 mo in seven patients with active pulmonary tuberculosis. We examined the presence of VEGF in the resected lungs of three patients with active pulmonary tuberculosis by immunohistochemistry. The serum levels of VEGF were significantly higher in patients with active pulmonary tuberculosis than in patients with old tuberculosis and acute bronchitis. The decrease in titer of serum VEGF paralleled the clinical improvement of patients with pulmonary tuberculosis. Immunohistochemical staining of the resected lungs demonstrated the presence of VEGF in alveolar macrophages surrounding the lesion. Therefore, VEGF may be associated with the pathogenesis of pulmonary tuberculosis.

Thrombocytes are the major source for soluble vascular endothelial growth factor in peripheral blood

Serum levels of vascular endothelial growth factor (VEGF-S) have been reported to correlate with tumor stage and prognosis in various human malignancies. The source of soluble VEGF in peripheral blood remains obscure. We therefore measured the concentration of immunoreactive VEGF in 241 serum samples and 61 plasma samples (VEGF-P) from 20 subjects undergoing myeloablative chemotherapy and from 3 normal platelet donors. A significant correlation between the peripheral blood platelet count (PC) and VEGF-S (r = 0.86) but not VEGF-P was found. VEGF-S levels were 58.43 +/- 42.50 pg/ml (mean +/- SD) in patients with a PC < 50 x 10(9)/l, 203.29 +/- 176.56 pg/ml for a PC of 50-150 x 10(9)/l, and 457.42 +/- 475.41 pg/ml for a PC > 150 x 10(9)/l. Interestingly, VEGF-P levels were substantially lower than the corresponding VEGF-S values, namely below the detection limit in most cases. Supernatants from platelet-rich plasma contained no VEGF, but after in vitro lysis of the platelets very high VEGF levels were found. The VEGF content per 10(9) platelets was calculated at 2.51 +/- 2.39 pg and was dependent on the mean platelet volume. In summary, VEGF release from platelets during blood clotting was found to be the main source of VEGF in serum samples. Cancer patients in clinical remission have negligible amounts of soluble VEGF in peripheral blood, and myeloablative chemotherapy causes a significant drop in VEGF-S levels corresponding to the decrease in PC. Thus, studies addressing the diagnostic and prognostic value of VEGF-S in cancer patients must be interpreted with caution. Our data provide the basis for predicting VEGF-S in relation to PC in vivo, and for reevaluating former studies of VEGF-S in patients with malignant or nonmalignant disease.

The relationship between angiogenesis and the immune response in carcinogenesis and the progression of malignant disease

Recent studies have demonstrated that angiogenesis and suppressed cell-mediated immunity (CMI) play a central role in the pathogenesis of malignant disease facilitating tumour growth, invasion and metastasis. In the majority of tumours, the malignant process is preceded by a pathological condition or exposure to an irritant which itself is associated with the induction of angiogenesis and/or suppressed CMI. These include: cigarette smoking, chronic bronchitis and lung cancer; chronic oesophagitis and oesophageal cancer; chronic viral infections such as human papilloma virus and ano-genital cancers, chronic hepatitis B and C and hepatocellular carcinoma, and Epstein-Barr virus (EBV) and lymphomas; chronic inflammatory conditions such as Crohn's disease and ulcerative colitis and colorectal cancer; asbestos exposure and mesothelioma and excessive sunlight exposure/sunburn and malignant melanoma. Chronic exposure to growth factors (insulin-like growth factor-I in acromegaly), mutations in tumour suppressor genes (TP53 in Li Fraumeni syndrome) and long-term exposure to immunosuppressive agents (cyclosporin A) may also give rise to similar environments and are associated with the development of a range of solid tumours. The increased blood supply would facilitate the development and proliferation of an abnormal clone or clones of cells arising as the result of: (a) an inherited genetic abnormality; and/or (b) acquired somatic mutations, the latter due to local production and/or enhanced delivery of carcinogens and mutagenic growth factors. With progressive detrimental mutations and growth-induced tumour hypoxia, the transformed cell, to a lesser or greater extent, may amplify the angiogenic process and CMI suppression, thereby facilitating further tumour growth and metastasis. There is accumulating evidence that long-term treatment with cyclo-oxygenase inhibitors (aspirin and indomethacin), cytokines such as interferon-alpha, anti-oestrogens (tamoxifen and raloxifene) and captopril significantly reduces the incidence of solid tumours such as breast and colorectal cancer. These agents are anti-angiogenic and, in the case of aspirin, indomethacin and interferon-alpha have proven immunomodulatory effects. Collectively these observations indicate that angiogenesis and suppressed CMI play a central role in the development and progression of malignant disease.