Tissue examination to monitor antiangiogenic therapy: a phase I clinical trial with endostatin.

PURPOSE: The purpose of this study was to determine the effect of the angiogenesis inhibitor endostatin on blood vessels in tumors and wound sites. EXPERIMENTAL DESIGN: In a Phase I dose escalation study, cancer patients were treated with daily infusions of human recombinant endostatin. Tumor biopsies were obtained prior to and 8 weeks after initiation of treatment. Blood vessel formation in nonneoplastic tissue was evaluated by creating a skin wound site on the arm with a punch biopsy device. The wound site was sampled with a second biopsy after a 7-day interval. This sequential biopsy procedure was performed prior to and 3 weeks after initiation of endostatin treatment. Vascular density, endothelial cell kinetics, and blood vessel maturity were determined in tumor and skin wound samples. The ultrastructure of tumor blood vessels was examined by electron microscopy. RESULTS: As expected, the tumors were of variable vascular density. Skin wounding induced a vascular granulation tissue containing a high percentage of proliferating endothelial cells. The proportion of immature blood vessels was high in tumors and in wound sites and low in normal skin. No statistically significant difference was detected between pretreatment and treatment samples of tumors and of skin wounds for any of the parameters tested. CONCLUSIONS: Endostatin treatment was not associated with any recognizable vascular changes in tumor samples and did not perturb wound healing at the doses and the treatment schedule used.

Blood flow distribution in necrotic versus nonnecrotic rabbit hearts.

The spatial myocardial blood flow heterogeneity of the normal heart was previously investigated by means of the standard microsphere-defined regional myocardial blood flow in nonischemic hearts. We determined the probability density functions of coronary blood flows in the rabbit heart at selected macroautoradiographic 20-microns cross-sections of the left ventricle in nonischemic as well as infarcted hearts. Macroautoradiography gave us spatial resolutions of 0.1-0.2 mm. As a tracer we used 14C-iodoantipyrine given into the root of the aorta. We report here for the first time a systematic study of the shape of the flow probability density functions during acute regional myocardial necrosis. As the hearts became progressively and extensively necrotic, the distribution of flows changed its characteristics showing two independent components. The first component was the peak representing the nonischemic regions in the hearts subjected to acute ischemia. The second component was a monotonically decreasing component associated with very low flows and necrosis in the severely hypoperfused portion of the hearts. This monotonically decreasing component became larger as the extent of ischemia increased and was well separated from the peak attributable to the nonischemic regions. We could not demonstrate a leftward shift of the nonischemic central peak in the ischemic hearts. Our research shows that in transaxial radionuclide cardiac sections, such as those that might be obtained and analyzed in clinical SPECT and clinical PET, variable amounts of myocardial necrosis will result in a composite curve of myocardial blood flow heterogeneities. One portion of the curve will indicate the distribution of flows in the nonischemic zones. The other portion will vary in magnitude with the extent of ischemia, exhibit the shape of monotonically decreasing curve. Depending upon the spatial resolution of the radionuclide imaging technique utilized, a border zone will exist representing the interface between normally perfused and occluded vascular beds. In our investigation, it was found that the border zone determined statistically was consistently and significantly smaller than the border zone determined visually.

Assessment of function, perfusion, metabolism, and histology in hearts preserved with University of Wisconsin solution.

BACKGROUND: University of Wisconsin solution has shown promise for prolonged cardiac preservation. This study compared the effects of 24-hour cold storage and perfusion preservation techniques by assessment of function, perfusion, metabolism, and histological changes. METHODS AND RESULTS: Three groups of rabbit hearts (n = 6 each) were evaluated: 1) control with immediate reperfusion, 2) continuous perfusion preservation, and 3) cold storage. Hearts were reperfused for 30 minutes, and left ventricular systolic pressure (LVSP) was measured by isovolumetric balloon (LVEDP, 20 mm Hg). We used 201Tl to assess perfusion and 14C-acetate to assess metabolism by macroautoradiography. LVSP was similar for controls and hearts preserved with continuous perfusion (134.8 +/- 2.1 versus 112.2 +/- 6.0 mm Hg, respectively). Hearts preserved with cold storage techniques were significantly worse (36.7 +/- 6.0 versus 134.4 +/- 8.2 mm Hg, p < 0.001). Controls showed homogeneous perfusion and metabolism, whereas hearts in the continuous perfusion group showed mild hypoperfusion and histological damage (26.4 +/- 2.7% of left ventricular cross section). Hearts in the cold storage group had 51.7 +/- 1.2% of the left ventricle hypoperfused and damaged. Histology in the control group was normal; in the perfused group, there were only mild changes; and in the cold storage group, there were extensive derangements of cellular architecture. CONCLUSIONS: Continuous perfusion of the heart with 4 degrees C modified University of Wisconsin solution provided function comparable to that of control. Conversely, cold storage showed extremely poor return of function. Autoradiography confirmed mild perfusion and metabolism abnormalities in control and continuous perfusion hearts, whereas there was marked derangement of cellular architecture, perfusion, and metabolism in the cold storage hearts.