Specific imaging of VEGF-A expression with radiolabeled anti-VEGF monoclonal antibody.

Vascular endothelial growth factor-A (VEGF-A) is one of the most important angiogenic factors. Here, we studied in a nude mouse model whether the expression of VEGF-A in a tumor could be imaged with a radiolabeled anti-VEGF antibody. The humanized anti-VEGF-A antibody A.4.6.1. (bevacizumab), which is reactive with all VEGF-A isoforms, was radiolabeled with In-111 or with I-125. The accumulation of the radiolabeled antibodies in VEGF-A expressing tumors (LS174T) in nude mice was examined in biodistribution studies and by gamma camera imaging. The uptake of the In-111-bevacizumab in the tumor at 3 days p.i. was significantly higher than that of I-125-bevacizumab (19.4 +/- 7.0 %ID/g vs. 9.6 +/- 3.3 %ID/g, p = 0.04). Coinjection of an excess unlabeled antibody resulted in a significant decrease in radioactivity concentration in the tumor (<2.9 +/- 1.9 %ID/g, p < 0.005), indicating VEGF-mediated antibody uptake. Highest uptake in the tumor was observed at relatively low antibody protein doses (<3 microg) (20-25 %ID/g). VEGF-A-expressing tumors could be clearly visualized on planar scintigraphic images from 24-hr post injection onwards. In conclusion, VEGF-A expression in tumors can be visualized specifically with radiolabeled anti-VEGF-A-mAb.

Increased metabolic activity of indolent liver metastases after resection of a primary colorectal tumor.

UNLABELLED: In murine models, resection of a primary tumor leads to increased vascularization and accelerated growth of metastases that previously had remained microscopic. To study such a potentially inhibitory effect of primary tumors on the outgrowth of distant metastases in humans, we assessed the metabolic activity of liver metastases by 18F-FDG PET before and after resection of primary colorectal tumors. METHODS: Group A consisted of 8 patients with synchronous colorectal liver metastases who were scheduled for resection of their primary tumor. These patients underwent an (18)F-FDG PET scan shortly before resection and 2-3 wk after resection of the primary tumor. The patients in a control group (group B, n = 9) underwent an 18F-FDG PET scan at the time of diagnosis of the liver metastases and a second scan several weeks later, before initiating treatment. There was no surgical intervention between the two 18F-FDG PET scans in this group. RESULTS: In group A, the maximum and mean standardized uptake values of the liver metastases clearly increased after resection of the primary tumor, by 38% +/- 55% and 42% +/- 52%, respectively, as compared with the first 18F-FDG PET scan. In group B, the maximum and mean standardized uptake values of the second 18F-FDG PET scan were not significantly higher than those of the first 18F-FDG PET scan; -11% +/- 23% and 1% +/- 29%, respectively. The difference in standardized uptake value increase between the 2 groups was statistically significant (P < 0.05). CONCLUSION: Our data cannot differentiate between the immunologic sequels caused by the surgical trauma itself and those caused by removal of the primary tumor. The observation itself, however, of increased metabolic activity after surgical resection of the primary tumor may have direct clinical applications and suggests the administration of antiangiogenic therapy after surgery of the primary tumor.

Decreased mortality but increased morbidity in neonates with jejunoileal atresia; a study of 114 cases over a 34-year period.

PURPOSE: The aim of the study was to evaluate patient demographics, classification and location of the atresia, operative management, postoperative care, and outcome in 114 infants with jejunoileal atresia (JIA) over a period of more than 3 decades. METHODS: This was a retrospective case series in a tertiary care teaching hospital. Records of all patients with JIA treated at the authors' institution between 1971 and 2004 were examined. RESULTS: Sixty-two percent of atresia and stenosis was noted in the jejunum, 30% in the ileum, and 8% in both the jejunum and the ileum. Atresias and stenosis were classified as follows: 7% type 0, 16% type I, 21% type II, 24% type IIIa, 10% type IIIb, 22% type IV. Gastrointestinal anomalies were encountered in 24% of patients, genitourinary malformations in 9%, cystic fibrosis in 9%, neurologic anomalies in 6%, and congenital heart disease in 4%. Operative management included resection with primary anastomosis in 69% of all patients and temporary enterostomies in 26%. After operative management, 15% of children had resultant short bowel syndrome. Oral feeding was allowed on median day 7, and full energy expenditure via the enteric route was reached on median day 20. Forty-seven percent of infants required central venous line placement for total parenteral nutrition. Early postoperative complications occurred in 28% of patients with JIA and late postoperative complications in 17%. We observed a mortality rate of 11%. CONCLUSIONS: This is one of the largest series of neonates with JIA described. Short bowel syndrome seems to be the biggest problem resulting in longer hospital stay, more feeding problems, and higher morbidity and mortality rates. Management of children with short bowel syndrome has improved because of the use of total parenteral nutrition, new operative techniques, and better intensive care. In the last 15 years, survival has increased at the cost of the surviving children as we noted a higher percentage of late complications.

Tumor accumulation of radiolabeled bevacizumab due to targeting of cell- and matrix-associated VEGF-A isoforms.

PURPOSE: Vascular endothelial growth factor-A (VEGF-A) is one of the most important factors inducing angiogenesis in tumors. Nine splice-variant isoforms of VEGF-A have been identified, each having different properties. Recently, we showed that radiolabeled anti-VEGF monoclonal antibody, bevacizumab, accumulates specifically in VEGF-A expressing tumors. In this study, we investigated in a nude mouse model which VEGF-isoforms are responsible for tumor accretion. MATERIALS AND METHODS: The humanized anti-VEGF-A antibody, A.4.6.1. (bevacizumab), was radiolabeled with In-111. The originally VEGF-negative Mel57 tumor was transfected with different VEGF isoforms (VEGF-121, VEGF-165, and VEGF-189). The obtained melanoma xenografts specifically expressing different VEGF-isoforms were used in mice. The bevacizumab uptake was examined in biodistribution studies and by gamma-camera imaging. RESULTS: The tumor cell line expressing VEGF-121 did not show specific uptake, most likely as a result of the fact that this isoform is freely diffusible. Tumors expressing VEGF-165 and -189 were clearly visualized by using gamma-camera imaging. CONCLUSION: The accumulation of radiolabeled bevacizumab in the tumor is due to interaction with VEGF-A isoforms that are associated with the tumor cell surface and/or the extracellular matrix. Scintigraphic imaging of the expression of these VEGF isoforms may thus be useful to predict response to angiogenic therapy.

Imaging liver metastases of colorectal cancer patients with radiolabelled bevacizumab: Lack of correlation with VEGF-A expression.

AIM OF THE STUDY: To investigate the correlation between tumour accumulation of In-111-bevacizumab and VEGF-A expression in patients with colorectal liver metastases. METHODS: Two weeks before resection of the liver metastases 12 patients were intravenously injected with In-111-labelled bevacizumab. Ten minutes and 7 d after injection a whole body scan was acquired. Seven days after the injection, 3D acquisition SPECT of the liver was performed. RESULTS: Enhanced uptake of In-111-bevacizumab in the liver metastases was observed in 9 of the 12 patients. The level of antibody accumulation in these lesions varied considerably. There was no correlation between the level of In-111-antibody accumulation and the level of VEGF-A expression in the tissue as determined by in situ hybridisation and ELISA. CONCLUSIONS: In this study, we investigated the correlation between tumour accumulation of radiolabelled bevacizumab and VEGF-A expression in patients with colorectal liver metastases. No clear-cut correlation between the level of antibody accumulation and expression of VEGF-A was found.