Microvascular structure of benign and malignant tumors of the colon in humans

In vivo pilot study into superficial microcirculatory characteristics of colorectal adenomas using novel high-resolution magnifying endoscopy with blue laser imaging

BACKGROUND

No studies have yet been conducted on changes in microcirculatory hemodynamics of colorectal adenomas in vivo under endoscopy. The microcirculation of the colorectal adenoma could be observed in vivo by a novel high-resolution magnification endoscopy with blue laser imaging (BLI), thus providing a new insight into the microcirculation of early colon tumors.

AIM

To observe the superficial microcirculation of colorectal adenomas using the novel magnifying colonoscope with BLI and quantitatively analyzed the changes in hemodynamic parameters.

METHODS

From October 2019 to January 2020, 11 patients were screened for colon adenomas with the novel high-resolution magnification endoscope with BLI. Video images were recorded and processed with Adobe Premiere, Adobe Photoshop and Image-pro Plus software. Four microcirculation parameters: Microcirculation vessel density (MVD), mean vessel width (MVW) with width standard deviation (WSD), and blood flow velocity (BFV), were calculated for adenomas and the surrounding normal mucosa.

RESULTS

A total of 16 adenomas were identified. Compared with the normal surrounding mucosa, the superficial vessel density in the adenomas was decreased (MVD: 0.95 ± 0.18 vs 1.17 ± 0.28 μm/μm2, P < 0.05). MVW (5.11 ± 1.19 vs 4.16 ± 0.76 μm, P < 0.05) and WSD (11.94 ± 3.44 vs 9.04 ± 3.74, P < 0.05) were both increased. BFV slowed in the adenomas (709.74 ± 213.28 vs 1256.51 ± 383.31 μm/s, P < 0.05).

CONCLUSION

The novel high-resolution magnification endoscope with BLI can be used for in vivo study of adenoma superficial microcirculation. Superficial vessel density was decreased, more irregular, with slower blood flow.

Simulation of transvascular transport of nanoparticles in tumor microenvironments for drug delivery applications

Nanomedicine is a promising approach for tumor therapy but penetration is challenged by complex tumor microenvironments. The purpose of this study is to design nanoparticles and analyze their transport in two abnormal microenvironments through a 2-D simulation. Employing a Computational Fluid Dynamics (CFD) approach, tumor vascular-interstitial models were initially simulated, and the impact of nanoparticles on the velocity profile and pressure gradient within the tumor microenvironment was observed. Through meticulous mesh analysis, it was determined that optimal outcomes were achieved using a quadrilateral meshing method for pancreatic tumor and a quad/tri meshing method for hepatic tumor. Results showed an increase in vessel diameter correlated with elevated blood flow velocity, reaching a maximum of 1.40 × 10^-3 m/s with an expanding cell gap. The simulation results for pressure distribution show that as vessel diameter increases, the velocity of nanoparticles in blood increases and decreases the pressure of blood. Intriguingly, distinct fluid flow patterns in pancreatic and hepatic tumors, emphasize how microenvironmental differences, specifically cell pore size, profoundly impact therapeutic agent transport, with implications for drug delivery strategies in cancer therapy. These simulation-based insights enable researchers to anticipate nanofluid behavior in realistic settings. Future work, incorporating immune cells, will enhance the understanding of nanoparticle efficiency in cancer therapy.

A comparative study of magnifying endoscopy with narrow-band image and endocytoscopy in the diagnosis of gastric neoplasm: a pilot study

BACKGROUND/AIMS

Endoscopic technologies have recently advanced to optimize the detection and diagnosis of gastric lesions. Endocytoscopy aids in the virtual realization of histology. Herein, we aimed to investigate gastric lesions using single-stain endocytoscopy and compare them using magnifying endoscopy with narrow-band imaging (ME-NBI) in terms of diagnostic yield in vivo.

METHODS AND METHODS

In the present prospective study, we registered 24 patients with gastric neoplasms and retrospectively reviewed their images. Three endoscopists reviewed the images of gastric neoplasms using white light, ME-NBI, and endocytoscopy. The diagnostic yield of endocytoscopy in early gastric cancer (EGC) was assessed using histopathology as the gold standard.

RESULTS

Endocytoscopy was performed in 24 patients with gastric neoplasms. Of these, 15 patients had adenocarcinomas, while nine patients had low-grade dysplasia. The sensitivity, specificity, and accuracy of endocytoscopy for EGC detection were reported as 80.0% [95% confidence interval (CI), 51.9-95.7], 66.7% (95% CI, 58.4-91.9), and 75.0% (95% CI, 53.3-90.2) by endoscopist A; 80.0% (95% CI, 51.9-95.7), 44.4% (95% CI, 13.7-78.8), and 66.7% (95% CI, 44.7-84.4) by endoscopist B; and 93.3% (95% CI, 68.1-99.8), 55.6% (95% CI, 21.2-86.3), and 79.2% (95% CI, 57.9-92.8) by endoscopist C; these findings were not inferior to NBI. The inter-observer agreement, κ statistic = 0.67 (95% CI, 0.43-0.90) was favorable.

CONCLUSION

Endocytoscopy aid in the diagnosis of EGC because of its better sensitivity and accuracy compared to NBI or white-light imaging. However, further large-scale studies are required to confirm our findings.

Shear wave elastography and pulsed doppler for breast lesions: Similar diagnostic performance and positively correlated stiffness and blood flow resistance

PURPOSE

To compare the diagnostic performance of shear wave elastography (SWE) and pulsed Doppler ultrasound in breast lesions, and to explore whether the quantitative SWE parameters correlated with pulsed Doppler ultrasound parameters.

MATERIALS AND METHODS

Seventy-nine patients with 79 breast lesions who had undergone conventional ultrasound, pulsed Doppler ultrasound and SWE examination were included. All of them underwent core needle biopsy or surgery within one week. Parameters including Emax (the maximum elastic modulus), Emean (mean elastic modulus), Emin (minimum elastic modulus), Esd (elastic modulus standard deviation), and RI (resistive index), PI (pulsatility index), PSV (peak systolic velocity) and EDV (end diastolic velocity) were obtained for statistical analysis.

RESULTS

Almost all SWE parameters were significantly different between benign and malignant breast lesions (P＜0.05). There was no significant difference between Esd and PI (P＞0.05), which had the best AUC among SWE and vascular parameters respectively (0.877 vs. 0.871). Emax showed a moderate correlation with PI (P = 0.000, r = 0.552) and RI (P = 0.000, r = 0.544), and Esd moderately correlated with PI (P = 0.000, r = 0.567) and RI (P = 0.000, r = 0.546). For the benign group, no parameters showed any significant correlation (P＞0.05), while for the malignant group, Emax and Esd also significantly correlated with PI or RI.

CONCLUSIONS

SWE and pulsed Doppler ultrasound had similar diagnostic efficacy for breast lesions. SWE and pulsed Doppler parameters were significantly correlated in breast lesions, especially in malignant ones, indicating the potential association between elastographic and vascular characteristics of breast tumors.

A detailed comparison between the endoscopic images using blue laser imaging and three-dimensional reconstructed pathological images of colonic lesions

Blue laser/light imaging (BLI) is an image-enhanced endoscopy (IEE) technique that can provide an accurate diagnosis by closely observing the surface structure of various colonic lesions. However, complete correspondence between endoscopic images and pathological images has not been demonstrated. The aim of this study was to accurately compare endoscopic images and the pathological images using a three-dimensionally (3D) reconstructed pathological model. Continuous thin layer sections were prepared from colonic tissue specimens and immunohistochemically stained for CD34 and CAM5.2. Three-dimensional reconstructed images were created by superimposing immunohistochemically stained pathological images. The endoscopic image with magnifying BLI was compared with the top view of the 3D reconstructed image to identify any one-to-one correspondence between the endoscopic images and histopathological images using the gland orifices and microvessels as a guide. Using 3D reconstructed pathological images, we were able to identify the location on the endoscope image in cases of colonic adenocarcinoma, adenoma and normal mucosa. As a result, the horizontal plane of the endoscopic image and the vertical plane of the 2D pathological specimen were able to be compared, and we successfully determined the visible blood vessel depth and performed a detailed evaluation on magnifying BLI. Examples are as follows: (1) The median vasculature depth from the mucosal surface that could be recognized as vasculature on magnifying BLI was 29.4 μm. The median depth of unrecognizable vessels on magnifying BLI was 218.8 μm, which was significantly deeper than recognizable vessels. (2) Some brownish structures were suggested to potentially be not only dense vessels, vessel expansions, corrupted vessels but also bleeding or extravasation of erythrocytes. Overall, we demonstrated a new approach to matching endoscopic images and pathological findings using a 3D-reconstructed pathological model immunohistochemically stained for CD34 and CAM5.2. This approach may increase the overall understanding of endoscopic images and positively contribute to making more accurate endoscopic diagnoses.

Biochemical and molecular aspects of 1,2-dimethylhydrazine (DMH)-induced colon carcinogenesis: a review

1,2-dimethylhydrazine (DMH) is a member in the class of hydrazines, strong DNA alkylating agent, naturally present in cycads. DMH is widely used as a carcinogen to induce colon cancer in animal models. Exploration of DMH-induced colon carcinogenesis in rodent models provides the knowledge to perceive the biochemical, molecular, and histological mechanisms of different stages of colon carcinogenesis. The procarcinogen DMH, after a series of metabolic reactions, finally reaches the colon, there produces the ultimate carcinogen and reactive oxygen species (ROS), which further alkylate the DNA and initiate the development of colon carcinogenesis. The preneolpastic lesions and histopathological observations of DMH-induced colon tumors may provide typical understanding about the disease in rodents and humans. In addition, this review discusses about the action of biotransformation and antioxidant enzymes involved in DMH intoxication. This understanding is essential to accurately identify and interpret alterations that occur in the colonic mucosa when evaluating natural or pharmacological compounds in DMH-induced animal colon carcinogenesis.

Temperature estimation of inflamed bowel by the photoacoustic inverse approach

Local temperature increase is one of the five classical signs of regions with inflammations. This work is focused on the application of the photoacoustic technique for the estimation of the temperature field in the colon, as the solution of an inverse problem, for the detection of inflamed regions. Two-dimensional cases are examined here involving a cross section of the bowel, which characterize either the inflammation of the whole mucosa layer, or three small inflamed regions. The inverse problem is solved for a rotating laser inside the intestine lumen, which imposes pulses for the generation of the acoustic waves. One single ultrasound detector, also located at the laser rotating shaft, provides the simulated measurements for the inverse analysis. The inverse problem is solved here with the minimization of the maximum a posteriori objective function. Results show that the proposed technique can be applied for accurate estimations of the temperature distribution in the region of interest, which might be used for the diagnosis of inflammatory bowel diseases (IBD).

MRI Simulation Study Investigating Effects of Vessel Topology, Diffusion, and Susceptibility on Transverse Relaxation Rates Using a Cylinder Fork Model

Brain vasculature is conventionally represented as straight cylinders when simulating blood oxygenation level dependent (BOLD) contrast effects in functional magnetic resonance imaging (fMRI). In reality, the vasculature is more complicated with branching and coiling especially in tumors. Diffusion and susceptibility changes can also introduce variations in the relaxation mechanisms within tumors. This study introduces a simple cylinder fork model (CFM) and investigates the effects of vessel topology, diffusion, and susceptibility on the transverse relaxation rates R2* and R2. Simulations using Monte Carlo methods were performed to quantify R2* and R2 by manipulating the CFM at different orientations, bifurcation angles, and rotation angles. Other parameters of the CFM were chosen based on physiologically relevant values: vessel diameters (~2‒10 µm), diffusion rates (1 × 10⁻¹¹‒1 × 10⁻⁹ m²/s), and susceptibility values (3 × 10⁻⁸–4 × 10⁻⁷ cgs units). R2* and R2 measurements showed a significant dependence on the bifurcation and rotation angles in several scenarios using different vessel diameters, orientations, diffusion rates, and susceptibility values. The angular dependence of R2* and R2 using the CFM could potentially be exploited as a tool to differentiate between normal and tumor vessels. The CFM can also serve as the elementary building block to simulate a capillary network reflecting realistic topological features.

Evaluation of microvascular findings of deeply invasive colorectal cancer by endocytoscopy with narrow-band imaging

Background and study aims: Magnifying narrow-band imaging (NBI) is useful for examination of colorectal lesions, and endocytoscopy (EC) allows diagnostic evaluation of structural atypia, nuclear atypia, and vascular structures of colorectal tumors. The aim of this study was to examine surface microvessels in deep invasive colorectal cancer using EC with a new NBI video processor system. Patients and methods: We retrospectively assessed 132 colorectal neoplastic lesions: 81 adenomas, 18 intramucosal cancers, 4 submucosal slightly invasive cancers, and 29 submucosal deep invasive cancers. Detailed vascular findings commonly seen in submucosal deep invasive carcinomas included > 2-fold vasodilatation seen in adenomas, abnormal tortuosity and branching, loss of the micro-network pattern, caliber change in > 2 places in a single blood vessel, and blood vessels not visible in a line because they appear like a string of beads (beaded sign). Results: Univariate analysis revealed 4 vascular findings that were strongly predictive of submucosal deep invasion: vasodilatation (odds ratio [OR] 9.31; 95 % confidence interval [CI] 3.57 - 24.30), loss of the micro-network pattern (OR 61.60; 95 % CI 17.87 - 212.29), caliber change (OR 35.7; 95 % CI 9.16 - 139.14), and the beaded sign (OR 45.90; 95 % CI 5.50 - 382.73). Conclusions: Detailed assessment of ultra-magnified microvessels could improve the diagnostic performance for submucosal deep invasive cancer.

STUDY REGISTRATION

UMIN-CTR000014033.

Endocytoscopic microvasculature evaluation is a reliable new diagnostic method for colorectal lesions (with video)

BACKGROUND

We previously reported on the efficacy of endocytoscopic classification (EC-C). However, the correlation of the endocytoscopic vascular (EC-V) pattern with diagnoses was unclear.

OBJECTIVE

To assess the diagnostic accuracy of the EC-V pattern for colorectal lesions.

DESIGN

Retrospective.

SETTING

A university hospital.

PATIENTS

Patients who underwent endocytoscopy between January 2010 and March 2013.

INTERVENTION

We evaluated 198 consecutive lesions according to the EC-V pattern (EC-V1, obscure surface microvessels; EC-V2, clearly observed surface microvessels of a uniform caliber and arrangement; and EC-V3, dilated surface microvessels of a nonhomogeneous caliber or arrangement).

MAIN OUTCOME MEASUREMENTS

The diagnostic accuracy for predicting hyperplastic polyps and invasive cancer were compared between the EC-V pattern and other modalities (narrow-band imaging, pit pattern, and EC-C).

RESULTS

The sensitivity, specificity, and accuracy of the EC-V1 pattern for diagnosing hyperplastic polyps were 95.5%, 99.4%, and 99.0%, respectively. The sensitivity, specificity, and accuracy of the EC-V3 pattern for diagnosing invasive cancer were 74.6%, 97.2%, and 88.6%, respectively. The diagnostic accuracy of the EC-V pattern for predicting hyperplastic polyps was comparable to the other modalities. For predicting invasive cancer, the EC-V pattern was comparable to narrow-band imaging and pit pattern, although EC-C was slightly more accurate (P = .04). In the substudy, the diagnosis time by using the EC-V pattern was shorter than that with the EC-C pattern (P < .001).

LIMITATIONS

A single-center, retrospective study.

CONCLUSIONS

The EC-V pattern saved more time than the EC-C pattern and had a diagnostic ability comparable to that of other optical biopsy modalities.

Prospective evaluation of endoscopic criteria characteristic of sessile serrated adenomas/polyps

BACKGROUND

Differentiating sessile serrated adenoma/polyp (SSA/P) from hyperplastic polyp (HP) is clinically important in determining the necessity of endoscopic resection or recommending appropriate surveillance. There are few reports of characterization of SSA/P using narrowband imaging and chromoendoscopy with and without magnification. We aimed to establish imaging criteria to aid real-time diagnosis of SSA/P.

METHODS

Patients with pale sessile or flat lesions of 6 mm or greater were prospectively enrolled in this multicenter trial. Nine endoscopic criteria, determined in real time, were investigated for possible association with SSA/P. Endoscopic mucosal resection was performed; specimens were retrieved and analyzed by histopathological examination.

RESULTS

In 63 patients, 89 lesions were detected, including 41 HP, 38 SSA/P, five mixed polyps, and five other lesions. Right-side colon location, lesion size of 10 mm or greater, excessive mucus, the presence of a varicose microvascular vessel (VMV) noted with high-magnification narrowband imaging, and type III(H) pit pattern were each commonly associated with SSA/P compared with HP. Multivariate analysis substantiated three independent endoscopic criteria for SSA/P: the presence of VMV (p = 0.001), lesion size of 10 mm or greater (p = 0.0017), and right-side location (p = 0.0041), with odds ratios of 8.2, 7.2, and 6.1, respectively. The presence of VMV had a significantly higher specificity (87.8%) than the other two independent endoscopic criteria (p = 0.0007 and p = 0.0008, respectively), but a lower sensitivity (57.9%), whereas a combination of the three criteria (two or more positive) increased the sensitivity significantly (89.5% and p = 0.0033) and had a higher degree of accuracy (82.3%).

CONCLUSIONS

Three endoscopic criteria individually and in combination were effective in predicting a diagnosis of SSA/P without the need for chromoendoscopy.

The contribution of neuronal-glial-endothelial-epithelial interactions to colon carcinogenesis

Several different cell types constitute the intestinal wall and interact in different manners to maintain tissue homeostasis. Elegant reports have explored these physiological cellular interactions revealing that glial cells and neurons not only modulate peristalsis and mechanical stimulus in the intestines but also control epithelial proliferation and sub-epithelial angiogenesis. Although colon carcinoma arises from epithelial cells, different sub-epithelial cell phenotypes are known to support the manifestation and development of tumors from their early steps on. Therefore, new perspectives in cancer research have been proposed, in which neurons and glial cells not only lead to higher cancer cell proliferation at the tumor invasion front but also further enhance angiogenesis and neurogenesis in tumors. Transformation of physiological neural activity into a pro-cancer event is thus discussed for colon carcinogenesis herein.

Blood flow resistance in lesion vessels and normal host vessels evaluated by pulsed Doppler ultrasound

Blood flow rate in the microcirculation is proportional to the arteriole-venule pressure difference and inversely proportional to the blood flow resistance (BFR). Generally, the BFR studies to date have focused on using invasive methods and were carried out in non-physiological conditions. Moreover, few studies have been concerned with the relationships of BFR between the tumor vessels and the normal host vessels. The present study investigated the BFR in malignant lesion vessels, benign lesion vessels and normal host vessels in physiological conditions using pulsed Doppler ultrasound as a tool and the thyroid as a model, A total of 133 patients with thyroid nodules were included in the study. The results revealed that most of the BFR parameters were higher in malignant lesion vessels than in benign lesion vessels (P=0.001-0.029), as well as lower in normal host vessels than in malignant or benign lesion vessels (P=0.000-0.017); Low to moderate significant positive correlations of BFR between benign lesion vessels and normal host vessels were also found (r=0.358-0.480, P=0.000 for all). Finally and interestingly, low negative correlations between the malignant nodule sizes and some of the BFR parameters were revealed, though these correlations were not statistically significant (r=-0.205--0.261, P=0.108-0.211). Our results suggested that pulsed Doppler ultrasound could be successfully used to measure BFR in physiological conditions and to reveal the BFR relationship between lesion vessels and normal host vessels, as well as the relationship between the lesion sizes and the BFR.

Fluoxetine induces preventive and complex effects against colon cancer development in epithelial and stromal areas in rats

Fluoxetine (FLX) is a drug commonly used as antidepressant. However, its effects on tumorigenesis remain controversial. Aiming to evaluate the effects of FLX treatment on early malignant changes, we analyzed serotonin (5-HT) metabolism and recognition, aberrant crypt foci (ACF), proliferative process, microvessels, vascular endothelial growth factor (VEGF), and cyclooxygenase-2 (COX-2) expression in colon tissue. Male Wistar rats received a daily FLX-gavage (30mgkg(-1)) and, a single dose of 1,2 dimethylhydrazine (DMH; i.p., 125mgkg(-1)). After 6 weeks of FLX-treatment, our results revealed that FLX and nor-fluoxetine (N-FLX) are present in colon tissue, which was related to significant increase in serotonin (5-HT) levels (P<0.05) possibly through a blockade in SERT mRNA (serotonin reuptake transporter; P<0.05) resulting in lower 5-hydroxyindoleacetic acid (5-HIAA) levels (P<0.01) and, 5-HT2C receptor mRNA expressions. FLX-treatment decreased dysplastic ACF development (P<0.01) and proliferative process (P<0.001) in epithelia. We observed a significant decrease in the development of malignant microvessels (P<0.05), VEGF (P<0.001), and COX-2 expression (P<0.01). These findings suggest that FLX may have oncostatic effects on carcinogenic colon tissue, probably due to its modulatory activity on 5-HT metabolism and/or its ability to reduce colonic malignant events.

Narrow-banding images and structures of microvessels of colonic lesions

BACKGROUND

Magnifying colonoscopy with NBI has been shown to be useful for the differential diagnosis of tumors. However, the relationship between findings on NBI magnification and the microvessel architecture of colorectal lesions remains to be clarified.

AIMS

The aim of this study was to clarify the correlation between NBI findings and the microvascular architecture of colorectal lesions according to the depth of microvessels from the mucosal surface.

METHODS

A total of 22 colorectal lesions (11 tubular adenomas and 11 hyperplasia) obtained from 22 patients were studied. These lesions were analyzed microscopically on tissue specimens immunostained with CD34. Three-dimensional images were reconstructed from serial sections of tubular adenomas, hyperplasia, and normal mucosa.

RESULTS

Three-dimensional reconstructed images of tubular adenoma and normal mucosa to a depth of less than 150 μm from the mucosal surface showed similar structures to images obtained by NBI magnification. Microvessel diameter was significantly larger in tubular adenoma than in normal mucosa (P = 0.002) and hyperplasia (P = 0.034), and microvessel area was significantly larger in tubular adenoma than in normal mucosa (P < 0.001) and hyperplasia (P < 0.001) only in the superficial mucosal layer (to a depth of less than 150 μm).

CONCLUSIONS

TA was characterized by thicker microvessels and higher volume of microvessels than NM and HP. Compared with white light, NBI can more accurately depict the characteristics of microvessels because it uses light with short wavelengths, thereby contributing to high diagnostic capability.

Computerized virtual chromoendoscopy versus indigo carmine chromoendoscopy combined with magnification for diagnosis of small colorectal lesions: a randomized and prospective study

BACKGROUND AND STUDY AIMS

Magnifying colonoscopy with indigo carmine dye and the analysis of the capillary and the pit patterns by computed virtual chromoendoscopy (Fujinon Intelligent Color Enhancement, FICE) with magnification are effective for the differential diagnosis of neoplastic and non-neoplastic lesions. This study aimed to compare the accuracy of virtual and real chromoendoscopy in differentiating neoplastic and non-neoplastic colorectal lesions.

PATIENTS AND METHODS

A prospective randomized trial of magnification colonoscopy with targeted FICE (Group I - 72 patients/111 lesions) versus magnification colonoscopy with targeted indigo carmine dye (Group II - 72 patients/137 lesions) was performed in consecutive patients with lesions 1 cm or less. Histopathology of the specimens was regarded as the gold standard.

RESULTS

In group I, 86 (77.5%) lesions showed an intense vascular pattern (positive capillary meshwork), of which 80 (93%) were histologically confirmed as adenomas. From 25 lesions with negative capillary meshwork, 23 (92%) were non-neoplastic. Sensitivity, specificity, accuracy, positive and negative predictive values of the capillary meshwork for the differential diagnosis of these lesions was 97.8, 79.3, 92.8, 93 and 92%, respectively. The same parameters for pit pattern analysis by FICE were 92.7, 82.3, 90.1, 93.8 and 80%, respectively. Indigo carmine magnified chromoscopy showed sensitivity, specificity, accuracy, positive and negative predictive values of 97, 88.9, 94.9, 96.1 and 91.4%, respectively in the discrimination between neoplastic and non-neoplastic lesions.

CONCLUSION

Magnified virtual chromoendoscopy is as accurate as indigo carmine magnified chromoendoscopy in distinguishing between neoplastic from non-neoplastic small colorectal lesions.

The spatial arrangement of the human large intestinal wall blood circulation

The aim of the study was to describe and depict the spatial arrangement of the colon microcirculatory bed as a whole. Various parts of the large intestine and terminal ileum were harvested from either cadaver or section material or gained peroperatively. Samples were then injected with India ink or methylmetacrylate Mercox resin for microdissection and corrosion casting for scanning electron microscopy. The results showed that extramural vasa recta ramified to form the subserous plexus, some of them passing underneath the colon taeniae. Branches of both short and long vasa recta merged in the colon wall, pierced the muscular layer and spread out as the submucous plexus, which extended throughout the whole intestine without any interruption. The muscular layer received blood via both the centrifugal branches of the submucous plexus and the minor branches sent off by the subserous plexus. The mucosa was supplied by the mucous plexus, which sent capillaries into the walls of intestinal glands. The hexagonal arrangement of the intestinal glands reflected their vascular bed. All three presumptive critical points are only gross anatomical points of no physiological relevance in healthy individuals. Neither microscopic weak points nor regional differences were proven within the wall of the whole large intestine. The corrosion casts showed a huge density of capillaries under the mucosa of the large intestine. A regular hexagonal pattern of the vascular bed on the inner surface was revealed. No microvascular critical point proofs were confirmed and a correlation model to various pathological states was created.

Assessment of tumour hypoxia for prediction of response to therapy and cancer prognosis

Tumour cells exploit both genetic and adaptive means to survive and proliferate in hypoxic microenvironments, resulting in the outgrowth of more aggressive tumour cell clones. Direct measurements of tumour oxygenation, and surrogate markers of the hypoxic response in tumours (for instance, hypoxia inducible factor-1α, carbonic anhydrase 9 and glucose transporter-1) are well-established prognostic markers in solid cancers. However, individual markers do not fully capture the complex, dynamic and heterogeneous hypoxic response in cancer. To overcome this, expression profiling has been employed to identify hypoxia signatures in cohorts or models of human cancer. Several of these hypoxia signatures have demonstrated prognostic significance in independent cancer datasets. Nevertheless, individual hypoxia markers have been shown to predict the benefit from hypoxia-modifying or anti-angiogenic therapies. This review aims to discuss the clinical impact of translational work on hypoxia markers and to explore future directions for research in this area.

Dynamics of different-sized solid-state nanocrystals as tracers for a drug-delivery system in the interstitium of a human tumor xenograft

INTRODUCTION

Recent anticancer drugs have been made larger to pass selectively through tumor vessels and stay in the interstitium. Understanding drug movement in association with its size at the single-molecule level and estimating the time needed to reach the targeted organ is indispensable for optimizing drug delivery because single cell-targeted therapy is the ongoing paradigm. This report describes the tracking of single solid nanoparticles in tumor xenografts and the estimation of arrival time.

METHODS

Different-sized nanoparticles measuring 20, 40, and 100 nm were injected into the tail vein of the female Balb/c nu/nu mice bearing human breast cancer on their backs. The movements of the nanoparticles were visualized through the dorsal skin-fold chamber with the high-speed confocal microscopy that we manufactured.

RESULTS

An analysis of the particle trajectories revealed diffusion to be inversely related to the particle size and position in the tumor, whereas the velocity of the directed movement was related to the position. The difference in the velocity was the greatest for 40-nm particles in the perivascular to the intercellular region: difference = 5.8 nm/s. The arrival time of individual nanoparticles at tumor cells was simulated. The estimated times for the 20-, 40-, and 100-nm particles to reach the tumor cells were 158.0, 218.5, and 389.4 minutes, respectively, after extravasation.

CONCLUSIONS

This result suggests that the particle size can be individually designed for each goal. These data and methods are also important for understanding drug pharmacokinetics. Although this method may be subject to interference by surface molecules attached on the particles, it has the potential to elucidate the pharmacokinetics involved in constructing novel drug-delivery systems involving cell-targeted therapy.

Detectability of colorectal neoplastic lesions using a narrow-band imaging system: a pilot study

BACKGROUND AND AIM

Flat and depressed colorectal neoplastic lesions can be difficult to identify using conventional colonoscopy techniques. Narrow-band imaging (NBI) provides unique views especially of mucosal vascular network and helps in visualization of neoplasia by improving contrast. The aim of this study was to assess the feasibility of using NBI for colorectal neoplasia screening.

METHODS

Forty-seven consecutive patients, who underwent high definition colonoscopy (HDC) screening examinations revealing neoplastic lesions, were enrolled in our prospective study. No biopsies or resections were performed during the initial HDC, but patients in whom lesions were detected underwent further colonoscopies using NBI, with the results of the first examination blinded from the colonoscopist. They then received appropriate treatment. We compared diagnostic detection rates of neoplastic lesions for HDC and NBI procedures using total number of all identified neoplastic lesions as reference standard.

RESULTS

Altogether, 153 lesions were detected and analyzed in 43 patients. Mean diagnostic extubation times were not significantly different (P = 0.18), but the total number of lesions detected by NBI was higher (134 vs 116; P = 0.02). Based on macroscopic type, flat lesions were identified more often by NBI (P = 0.04). As for lesion size, only flat lesions < 5 mm were detected more frequently (P = 0.046). Lesions in the right colon were identified more often by NBI (P = 0.02), but NBI missed two flat lesions >or= 10 mm located there.

CONCLUSIONS

Narrow band imaging colonoscopy may represent a significant improvement in the detection of flat and diminutive lesions, but a future multi-center controlled trial should be conducted to fully evaluate efficacy for screening colonoscopies.

Narrow band imaging with magnifying colonoscopy as diagnostic tool for predicting histology of early colorectal neoplasia

BACKGROUND

The presence of abnormal microcapillaries detected by narrow band imaging (NBI) with magnifying colonoscopy has been reported to be a marker of colorectal neoplasia.

AIM

To investigate prospectively if NBI with magnification could help predict the histology of early colorectal neoplasia.

METHODS

A series of 104 consecutive patients with 139 colorectal lesions were studied. All lesions were detected by conventional colonoscopy and subsequently evaluated by NBI with magnification. During NBI with magnification, the microvascular architecture observed on the surface of the detected lesions, capillary patterns (CP), was divided into non-neoplastic (CP I) and neoplastic (CP II and CP III) types. Only lesions endoscopically diagnosed as CP II or CP III were included in the study. All of the lesions were resected endoscopically or surgically and examined histologically for comparison.

RESULTS

Ninety-seven per cent (n = 103) of colorectal neoplastic lesions with CP II were histologically diagnosed as low-grade dysplasia. Eighty-seven per cent (n = 31) of the colorectal neoplastic lesions with CP III were high-grade dysplasia or invasive cancer.

CONCLUSION

Capillary patterns observed by NBI with magnification could be used to assess the degree of atypia in early colorectal neoplasia.

Computed virtual chromoendoscopy for classification of small colorectal lesions: a prospective comparative study

OBJECTIVES

Standard colonoscopy offers no reliable discrimination between neoplastic and nonneoplastic colorectal lesions. Computed virtual chromoendoscopy with the Fujinon intelligent color enhancement (FICE) system is a new dyeless imaging technique that enhances mucosal and vascular patterns. This prospective trial compared the feasibility of FICE, standard colonoscopy, and conventional chromoendoscopy with indigo carmine in low- and high-magnification modes for determination of colonic lesion histology.

METHODS

Sixty-three patients with 150 flat or sessile lesions less than 20 mm in diameter were enrolled. At colonoscopy, each lesion was observed with six different endoscopic modalities: standard colonoscopy, FICE, and conventional chromoendoscopy with indigo carmine (0.2%) dye spraying in both low- and high-magnification modes. Histopathology of all lesions was confirmed by evaluation of endoscopic resection or biopsy specimens. Endoscopic images were stored electronically and randomly allocated to a blinded reader.

RESULTS

Of the 150 polyps, 89 were adenomas and 61 were hyperplastic polyps with an average size of 7 mm. For identifying adenomas, the FICE system with low and high magnifications revealed a sensitivity of 89.9% and 96.6%, specificity of 73.8% and 80.3%, and diagnostic accuracy of 83% and 90%, respectively. Compared with standard colonoscopy, the sensitivity and diagnostic accuracy achieved by FICE were significantly better under both low (P < 0.02) and high (P < 0.03) magnification and were comparable to that of conventional chromoendoscopy.

CONCLUSIONS

The FICE system identified morphological details that efficiently predict adenomatous histology. For distinguishing neoplastic from nonneoplastic lesions, FICE was superior to standard colonoscopy and equivalent to conventional chromoendoscopy.

Evaluation of microvessels in colorectal tumors by narrow band imaging magnification

BACKGROUND

Narrow band imaging (NBI) uses optical filters for sequential green and blue illumination and narrows the bandwidth of spectral transmittance.

OBJECTIVE

We determined the clinical usefulness of NBI magnification for evaluation of microvascular architecture and qualitative diagnosis of colorectal tumors.

DESIGN

This study was a retrospective study.

SETTING

Department of Endoscopy, Hiroshima University, Hiroshima, Japan.

PATIENTS AND MAIN OUTCOME MEASUREMENTS

A total of 189 colorectal lesions were analyzed. Each lesion was observed by NBI magnifying endoscopy and classified according to microvascular features (ie, thickness and irregularity). Microvessel thickness was classified as invisible, thin, or thick, and microvessel irregularity was classified as invisible, regular, mildly irregular, or severely irregular. NBI endoscopic images were compared with histologic findings.

RESULTS

With respect to microvessel thickness, invisible microvessels were found significantly more often in hyperplasia lesions, and thick microvessels were found significantly more often in carcinoma with submucosal massive invasion (sm-m) (P < .01). With respect to microvessel irregularity, invisible microvessels were found significantly often in hyperplasia lesions, and severely irregular microvessels were found significantly often in sm-m lesions (P < .01). Accuracy of diagnosis of sm-m on the basis of thick and severely irregular lesions was 100%.

CONCLUSION

Microvascular features determined by NBI magnification are associated with histologic grade and depth of submucosal invasion. These results indicate that NBI magnification is useful for the prediction of histologic diagnosis and selection of therapeutic strategies of colorectal tumors.

Peroral cholangioscopic diagnosis of biliary-tract diseases by using narrow-band imaging (with videos)

BACKGROUND

Narrow-band imaging (NBI) makes it possible to emphasize the imaging of certain features, such as mucosal structures and mucosal microvessels in GI-tract diseases. Recently, video peroral cholangioscopy (POCS) was developed as a diagnostic modality for better visualization of bile-duct lesions; however, there is no report on POCS by using NBI.

OBJECTIVE

To evaluate the clinical usefulness of POCS by using NBI for the diagnosis of biliary-tract diseases.

DESIGN

Prospective case study.

SETTING

This procedure was performed at Tokyo Medical University Hospital.

PATIENTS

Twelve consecutive patients with biliary-tract diseases, including 7 bile-duct cancers and 5 benign biliary diseases, which revealed 6 bile-duct strictures and 6 filling defects by ERCP.

INTERVENTION

All patients underwent POCS by using NBI.

MAIN OUTCOME MEASUREMENT

Efficacy and safety of this technique.

RESULTS

Twenty-one lesions were evaluated by using POCS with conventional white light imaging and NBI. Although visualization of only 2 lesions (9.5%) was "excellent" by conventional observation, visualization of 12 lesions (57.4%) was "excellent" by NBI observation. Identification of the surface structure and vessels of the lesions by NBI observation was significantly better than with conventional observation (P < .01 and P < .05, respectively).

LIMITATIONS

Maneuverability and fragility of POCS. The current POCS is not equipped with magnification.

CONCLUSIONS

POCS by using NBI may be helpful for the observation of both fine mucosal structures and tumor vessels.

Magnifying endoscopy with narrow band imaging for diagnosis of colorectal tumors

BACKGROUND

Narrow band imaging (NBI) uses optical filters for red-green-blue sequential illumination and narrows the bandwidth of spectral transmittance.

OBJECTIVE

This study aimed to clarify the clinical usefulness of NBI magnification in assessment of pit patterns for diagnosis of colorectal tumors.

DESIGN

This was a retrospective study.

SETTING

Department of Endoscopy, Hiroshima University Hospital.

PATIENTS AND MAIN OUTCOME MEASUREMENTS

A total of 148 colorectal lesions, 16 hyperplasias, 84 tubular adenomas, and 48 early carcinomas were examined and diagnosed histologically. Mean size of lesions was 15.6+/-7.28 mm. Lesions were observed first under NBI magnification without chromoendoscopy and then under standard magnification with chromoendoscopy, and pit patterns were recorded. Results of NBI magnification were compared with those of standard magnification with chromoendoscopy to assess the clinical usefulness of NBI magnification for diagnosing colorectal neoplasia.

RESULTS

Correspondence between the two diagnostic methods was 88% (14/16) for type II, 100% (2/2) for type IIIs, 98% (73/75) for type IIIl, 88% (7/8) for type IV, 78% (25/32) for type Vi, and 100% (3/3) for type Vn pit patterns. NBI depicted brownish change on the basis of surface capillaries in 6% (1/16) of hyperplasia and 99% (83/84) of tubular adenomas. This difference in color depiction was significant.

LIMITATIONS

This study was performed in single center.

CONCLUSIONS

Determination of pit patterns of colorectal neoplasias by NBI magnification was nearly the same as that by standard magnification with chromoendoscopy. Furthermore, NBI can distinguish neoplastic and nonneoplastic lesions without chromoendoscopy.

Real-time visualization and quantitation of canine gastric mucosal blood flow by contrast-enhanced ultrasonography

OBJECTIVE

Contrast-enhanced ultrasonography has become a method of choice for evaluating gastric blood flow, but intermittent scanning techniques can sometimes distort the results. Low-mechanical index imaging using Definity as the injected contrast material has been advocated for real-time evaluation of microperfusion in other organs. We investigated the reliability of low-mechanical index imaging using Definity in the evaluation of gastric mucosal blood flow.

MATERIAL AND METHODS

Under general anesthesia, 10 beagle dogs weighing 9-10 kg underwent real-time harmonic imaging under low acoustic power (mechanical index = 0.2) after intravenous contrast injection using Definity (60 mg/kg). Laser Doppler flow measurement was also performed to evaluate gastric mucosal blood flow. After administration of a diclofenac sodium suppository, low-mechanical index imaging and laser Doppler flowmetry were repeated.

RESULTS

Real-time visualization of gastric mucosal blood flow was successful in all dogs undergoing low-mechanical index imaging with Definity. Quantitative assessment of gastric mucosal blood flow was successful in eight dogs. After diclofenac sodium administration, gastric mucosal blood flow measured by both laser Doppler flowmetry and contrast ultrasonography decreased in seven of eight dogs; in the other dog, gastric mucosal blood flow increased slightly. A strong positive correlation was evident between blood flow measured by laser Doppler flowmetry and low-mechanical index imaging (r=0.777, p<0.005).

CONCLUSIONS

Low-mechanical index imaging with Definity is a non-invasive way to evaluate gastric mucosal blood flow in real-time, high-resolutional images, which may have additional important gastrointestinal tract applications.

Changes in vasoconstrictor and vasodilator neurotransmitters in nerves supplying arterioles in developing colorectal polyps

OBJECTIVE

To examine the changes that occur in the immunohistochemistry of vasoconstrictor and vasodilator transmitters in nerves supplying early and advanced colorectal polyps.

SUBJECTS AND METHODS

We studied the perivascular innervation of submucosal arterioles of colorectal polyps (n = 18) and the innervation of the epithelial layer of polyps compared to normal controls (n=8), using immunohistochemical markers for the neurotransmitters; noradrenaline (NA) (marker used; tyrosine hydroxylase (TH)), neuropeptide Y (NPY), vasoactive intestinal polypeptide (VIP), substance P (SP), and calcitonin gene-related polypeptide (CGRP). (Advanced polyps; villous adenomas>1.5 cm, polyps with severe dysplasia or partial carcinoma).

RESULTS

In submucosal arterioles there was a progressive decrease from controls through early polyps to advanced polyps in TH and NPY perivascular immunoreactivity (P<0.015 for both). VIP and SP immunoreactivity was higher in early polyps compared to controls, but markedly reduced in advanced polyps (P<0.05 for VIP). Sparse CGRP immunoreactivity was present in polyps only. Neural VIP and SP immunoreactivity in the lamina propria of polyp mucosa was more intense than in controls.

CONCLUSION

There is a decrease in vasoconstrictor neurotransmitters NPY and NA (shown by TH) around submucosal arterioles of both early and advanced polyps, but an increase in the vasodilator neurotransmitters, particularly VIP, in early colorectal polyps. These results suggest a predominantly vasodilatory neural influence in early polyps, perhaps indicating a mechanism that maintains polyp growth.

Endoscopic detection of early lower gastrointestinal cancer

The prognosis for patients with malignancies of the lower gastrointestinal tract is strictly dependent on early detection of premalignant and malignant lesions. What should an ideal screening and surveillance colonoscopy be able to accomplish? The technique should allow detection of large but also discrete mucosal alterations. Ideally, endoscopic discrimination between neoplastic and non-neoplastic lesions would be possible during the ongoing procedure. At present, endoscopy can be performed with powerful new endoscopes. Comparable to the rapid development in chip technology, the optical features of the newly designed endoscopes offer resolutions, which allow new surface details to be seen. In conjunction with chromoendoscopy, the newly discovered tool video colonoscopy is much easier and more impressive today than with the previously used fibre-optic endoscopes. Recently, new endoscopic technologies such as narrow band imaging, endocytoscopy, or confocal laser endoscopy have allowed the discovery of a whole new world of image details which will surely improve the diagnostic yield in the field of early malignancies. This review summarises newly available technologies and clinical data about the diagnosis of early lower gastrointestinal cancers.

Transcriptional targeting of acute hypoxia in the tumour stroma is a novel and viable strategy for cancer gene therapy

Deregulated tumour growth and neovascularization result in an inadequate tumour blood supply, leading to areas of chronic hypoxia and necrosis. Irregular vascular structure and abnormal tumour physiology also cause erratic blood flow in tumour vessels. We reasoned that tumour stroma, including vascular endothelial cells, would consequently experience transient hypoxia that may allow transcriptional targeting as part of an antivascular gene therapy approach to cancer. To exploit hypoxia for transcriptional regulation, retroviral vectors were generated with modified LTRs: a 6-mer of hypoxia response elements in place of the viral enhancer produced near wild-type levels of expression in hypoxia but was functionally inert in normoxia. In a tumour xenograft model, expression was mainly around areas of necrosis, which were shown to be hypoxic; no expression was detected in tumour stroma. Time-course experiments in vitro demonstrated that expression was transient in response to a hypoxic episode, such that a reporter gene would be insensitive to acute hypoxia in vivo. In contrast, a significant therapeutic effect was seen upon ganciclovir administration with a vector expressing thymidine kinase (TK) in the tumour stroma. Expression of TK was more effective when targeted to acute hypoxia in the stroma compared to chronic hypoxia in the poorly vascularized regions of the tumour cell compartment. The data presented here are evidence that hypoxia in the stromal compartment does occur and that transient hypoxia constitutes a valid therapeutic target.

Modelling and validation of spectral reflectance for the colon

The spectral reflectance of the colon is known to be affected by malignant and pre-malignant changes in the tissue. As part of long-term research on the derivation of diagnostically important parameters characterizing colon histology, we have investigated the effects of the normal histological variability on the remitted spectra. This paper presents a detailed optical model of the normal colon comprising mucosa, submucosa and the smooth muscle layer. Each layer is characterized by five variable histological parameters: the volume fraction of blood, the haemoglobin saturation, the size of the scattering particles, including collagen, the volume fraction of the scattering particles and the layer thickness, and three optical parameters: the anisotropy factor, the refractive index of the medium and the refractive index of the scattering particles. The paper specifies the parameter ranges corresponding to normal colon tissue, including some previously unpublished ones. Diffuse reflectance spectra were modelled using the Monte Carlo method. Validation of the model-generated spectra against measured spectra demonstrated that good correspondence was achieved between the two. The analysis of the effect of the individual histological parameters on the behaviour of the spectra has shown that the spectral variability originates mainly from changes in the mucosa. However, the submucosa and the muscle layer must be included in the model as they have a significant constant effect on the spectral reflectance above 600 nm. The nature of variations in the spectra also suggests that it may be possible to carry out model inversion and to recover parameters characterizing the colon from multi-spectral images. A preliminary study, in which the mucosal blood and collagen parameters were modified to reflect histopathological changes associated with colon cancer, has shown that the spectra predicted by our model resemble measured spectral reflectance of adenocarcinomas. This suggests that an extended model, which incorporates parameters corresponding to an abnormal colon, may be effective for differentiation between normal and cancerous tissues.

Three-dimensional structural changes in cerebral microvessels after transient focal cerebral ischemia in rats: scanning electron microscopic study of corrosion casts

Pathological changes of cerebral microvessels in transient ischemia were investigated by scanning electron microscopy of vascular corrosion casts. Wistar rats were treated with middle cerebral artery (MCA) occlusion for 30 min, 1 h, 3 h, 4 h, 5 h or 7 h and subsequent reperfusion for 2 h. The ultrastructures of the cast were observed and computer-aided montage micrographs were obtained for visualization of the whole microvasculature in the ischemic brain hemisphere. Avascular areas representing ischemic areas were detected in the frontotemporal cortex and caudate putamen in the groups from 30 min to 5 h occlusion. Extravasation of the resin, which probably corresponded to the leakage of plasma or hemorrhage, was seen as spheroidal, conglomerative, large massive and worm-like types. The spheroidal type, which probably indicated a small leakage or minor hemorrhage, began to appear in the 30-min occlusion group. The conglomerative type, which probably indicated a larger leakage or moderate hemorrhage, appeared in the 3- to 5-h occlusion groups. The large massive and worm-like types, which probably indicated a significant hemorrhage, appeared in the 4- and 5-h occlusion groups. The number of these extravasations increased significantly in the 4-h occlusion group. Arterioles near the avascular area frequently showed vasospastic appearances, such as corrugations, fusiform indentations of endothelial nuclei, continuous circulatory constrictions and severe narrowing with interrupted branches. Arteriolar vasospasm possibly caused prolonged hypoperfusion even if reperfusion was achieved. The capillaries had a thin stringy appearance in the 4- and 5-h occlusion groups. These changes seemed to relate closely with increased intracranial pressure by brain edema or hemorrhage. The present study suggested that the risk of brain edema or hemorrhagic infarction increased beyond 3 h of MCA occlusion, and vasospasm of the arterioles might participate in stroke pathophysiology.

Drug delivery and transport to solid tumors

PURPOSE

The purpose of this review is to provide an overview of the principles of and barriers to drug transport and delivery to solid tumors.

METHODS

This review consists of four parts. Part I provides an overview of the differences in the vasculature in normal and tumor tissues, and the relationship between tumor vasculature and drug transport. Part II describes the determinants of transport of drugs and particles across tumor vasculature into surrounding tumor tissues. Part III discusses the determinants and barriers of drug transport, accumulation, and retention in tumors. Part IV summarizes the experimental approaches used to enhance drug delivery and transport in solid tumors.

RESULTS

Drug delivery to solid tumors consists of multiple processes, including transport via blood vessels, transvascular transport, and transport through interstitial spaces. These processes are dynamic and change with time and tumor properties and are affected by multiple physicochemical factors of a drug, multiple tumor biologic factors, and as a consequence of drug treatments. The biologic factors, in turn, have opposing effects on one or more processes in the delivery of drugs to solid tumors.

CONCLUSION

The effectiveness of cancer therapy depends in part on adequate delivery of the therapeutic agents to tumor cells. A better understanding of the processes and contribution of these factors governing drug delivery may lead to new cancer therapeutic strategies.

ZD6126 inhibits orthotopic growth and peritoneal carcinomatosis in a mouse model of human gastric cancer

The purpose of this study was to examine the effects of ZD6126, a novel vascular-targeting agent, on tumour growth and angiogenesis in an orthotopic model of gastric cancer. TMK-1 human gastric adenocarcinoma cells were injected into the gastric wall of nude mice. After the tumours were established (day 14), therapy was initiated. Mice (n=11-12/group) received (a). vehicle, (b). ZD6126 at 100 mg x kg day(-1) i.p. one time per week or (c) ZD6126 at 100 mg x kg day(-1) i.p. five times per week. Tumour mass, volume and the presence or absence of peritoneal carcinomatosis were determined at sacrifice on day 38. Tumours from each group were stained for markers of blood vessels, proliferation and apoptosis. To further define the time frame of the vascular-targeting effects of chronic therapy with ZD6126, TMK-1 cells were again injected into the gastric wall of mice in a second experiment. On day 14, a single i.p. injection of ZD6126 100 mg x kg(-1) mouse(-1) or vehicle was delivered. Groups of three mice each were killed and the tumours harvested at days 1, 3 and 5 post-ZD6126 injection. Tumours were processed and stained for endothelial and tumour cell apoptosis and proliferation. No overt toxicity was observed with ZD6126 therapy. ZD6126 led to a marked inhibition of tumour growth (82% decrease vs control (P<0.001)). ZD6126 also led to a significant decrease in the incidence of peritoneal carcinomatosis (10 out of 12 controls, vs one out of 12 ZD6126) (P<0.01). Histological analysis of tumours revealed large regions of central necrosis in the treated group, as well as a dramatic increase in tumour cell apoptosis (7.4-fold increase (P<0.001)), consistent with the vascular-targeting activity of ZD6126. Mice treated with ZD6126 demonstrated a 59% decrease in PCNA-positive cells (P< 0.02), indicating reduced tumour cell proliferation. In addition, tumours treated with ZD6126 exhibited a 40% decrease in microvessel density (P<0.05). Results from mice treated with a single injection of ZD6126 demonstrated the acute effects this agent has on the tumour vasculature. The ratio of endothelial cell apoptosis to endothelial cell proliferation was increased within 24 h of a single injection. In conclusion, ZD6126 significantly inhibited tumour growth and metastasis in an orthotopic model of human gastric adenocarcinoma, without detectable problematic adverse effects. These data suggest that ZD6126 may be worthy of investigation in the treatment of primary gastric adenocarcinoma.

Angioarchitecture of tumors induced by two different cloned cell lines established from a transplantable rat malignant fibrous histiocytoma

Angiogenesis, a biologic process whereby endothelial cells divide and migrate to form new blood vessels, is a key step in tumor growth, invasion, and metastasis. In the present study, we investigated the differences in angioarchitecture between two different tumors induced by cloned cell lines (MT-8 and MT-9), derived from a transplantable rat malignant fibrous histiocytoma, by scanning electron microscopy of vascular corrosion casts. During a 3-week observation period after implantation, the growth of MT-8 tumors appeared to be faster than that of MT-9 tumors. Histologically, MT-8 tumors were of the uniformly undifferentiated sarcoma type arranged in characteristic organoid structures, and MT-9 tumors showed a storiform growth pattern. In MT-8 tumors, neovascularization occurred by sprouting at postimplantation (PI) week 1, and the newly formed capillaries gradually became more tortuous. In MT-9 tumors, at PI week 1, the corrosion casts of newly formed capillaries mainly showed a wavy course but no finger-like outgrowths of capillaries were seen. At PI weeks 2 and 3, the sprouting was seen specifically in MT-9 tumors, forming basket-like structures and glomeruloid structures of capillaries. These results indicate that angiogenesis or angioarchitecture of MT-8 tumors is different from that of MT-9 tumors, depending on the differences in their tumor histology and by the features like absence or presence of basket-like structures and glomeruloid structures of capillaries.

Microvessel morphology and vascular endothelial growth factor expression in human colonic carcinoma with or without metastasis

We quantified microvessel morphology and vascular endothelial growth factor (VEGF) expression in human colonic carcinoma with or without metastasis. The cancerous growth and the noncancerous section of surgical specimens from 36 patients with colorectal carcinoma (14 without metastasis and 22 with metastasis) were studied. Tissue slices immunostained with CD34 were processed for microvessel counts (per mm(2)), the mean diameter of microvessels (microm), and the mean spatial direction of microvessels (degree), defined by the angle between the longitudinal axis of microvessels and the direction perpendicular to the surface of the mucosa. Tissue slices immunostained with anti-VEGF antibody were processed for total epithelial cell counts (per mm(2)), VEGF-positive cell counts (per mm(2)), and VEGF-positive ratio (%). Carcinoma without metastasis had significantly larger microvessel counts (213 +/- 77, p < 0.01), larger microvessel diameter (7.99 +/- 1.77, p < 0.05), and larger spatial direction (47.2 +/- 8.3, p < 0.01) than normal tissue (144 +/- 49 for microvessel counts; 7.03 +/- 0.90 for microvessel diameter; 39.5 +/- 6.6 for spatial direction). Compared with carcinoma without metastasis, carcinoma with metastasis had a significantly larger microvessel diameter (9.75 +/- 2.65, p < 0.03) and lower microvessel counts (180 +/- 92, p = 0.51). Carcinoma without metastasis had a significantly larger VEGF-positive cell count (1276 +/- 805, p < 0.05) and larger VEGF-positive ratio (53.6 +/- 39.3, p < 0.05) than normal tissue (571 +/- 553 for VEGF-positive cell counts; 24.6 +/- 23.2 for VEGF-positive ratio). Carcinoma with metastasis had a significantly lower total cell count (1443 +/- 237, p < 0.001) and lower VEGF-positive cell count (716 +/- 463, p < 0.05) than carcinoma without metastasis. With tumor progression, microvessel diameter significantly increased and microvessel counts decreased, which can be in part explained by VEGF expression. The microvessel diameter seems to be the dominant parameter responsible for cancer cell intravasation as the first step of metastasis.

Progressive loss of perivascular nerves adjacent to colorectal cancer

AIMS

The perivascular innervation of arterioles in colorectal cancer and adjacent submucosa was investigated.

METHODS

Neurotransmitter markers, neuropeptide Y (NPY), vasoactive intestinal peptide (VIP), substance P (SP), calcitonin gene-related peptide (CGRP) and tyrosine hydroxylase (TH), were studied and immunoreactivity was compared with that of control normal tissue.

RESULTS

There was absence of perivascular nerves within tumours and loss of perivascular innervation in the submucosa adjacent to the tumour. The pattern of loss varied for different transmitters. The loss was progressively greater with advancing tumour stage for NPY (controls 95%, Dukes' A 68%, Dukes>> B 13%, Dukes' C 6%) and VIP (50%, 23%, 20%, 17%). For TH there was extensive loss of innervation around tumours of all stages (69%, 5%, 7%, 0%). SP immunoreactive peri-arteriolar nerves were similar in control tissue (39%) and tissue adjacent to Dukes' A tumours (40%) but diminished to 19% and 0% in tissue adjacent to Dukes' B and C tumours, respectively. In none of the tissues was CGRP immunoreactivity above 4%. The mean distance over which there was reduced NPY immunoreactivity from the tumour edge was 2.43 mm for Dukes' A/B tumours compared with 7.20 mm for Dukes' C tumours; for VIP immunoreactivity this distance was 5.22 mm for Dukes' A/B tumours and 5.52 mm for Dukes' C tumours.

CONCLUSIONS

The progressive loss, both in terms of vascular nerve immunoreactivity and distance from the tumour edge with tumour grade, suggests that the tumour itself may influence neural integrity in perivascular plexuses, perhaps via the secretion of an inhibitory factor.

Expressions of vascular endothelial growth factor and basic fibroblast growth factor in tumors induced by two different cloned cell lines established from transplantable rat malignant fibrous histiocytoma

In order to establish base-line data on angiogenic factors in development of mesenchymal tumors, expressions of vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) in implanted MT-8 and MT-9 tumors, both derived from a transplantable malignant fibrous histiocytoma (MFH) in the F344 rat, were investigated by immunohistochemistry and Western blotting method. MT-8 and MT-9 tumors were developed in syngeneic rats by implant of a tumor tissue fragment. MT-8 tumors were examined on post-implantation (PI) days 3, 6, 9 and 17, and MT-9 tumors were on PI days 9, 14, 17 and 23. The growth of MT-8 tumors was faster than that of MT-9 tumors. Histologically, MT-8 tumors were features of undifferentiated sarcomas, whereas MT-9 tumors exhibited a typical storiform growth pattern of MFH. Immunohistochemically, all cells constituting MT-8 and MT-9 tumors reacted with antibodies to VEGF and bFGF, indicating production of these factors by mesenchymal neoplastic cells. However, there were no marked differences in these immunoreactions between tumors examined. Thus, the bands obtained in the Western blotting methods were densitometrically scanned. The expression levels of VEGF and bFGF gradually increased PI day 3 to 9 in MT-8 tumors and PI day 9 to 17 in MT-9 tumors. On last examination day, the levels of bFGF in both tumors and of VEGF in MT-9 tumors decreased, but the VEGF expression level in MT-8 tumors was still increased. These findings indicated that VEGF and bFGF may contribute cooperatively to angiogenesis in an early growth of mesenchymal tumor development.

Expression of nuclear beta-catenin and c-myc is correlated with tumor size but not with proliferative activity of colorectal adenomas

Most colorectal cancers have loss-of-function mutations in the adenomatosis polyposis coli (APC) tumor suppressor gene. This leads to the accumulation of nuclear beta-catenin, which, together with the DNA-binding protein TCF-4, functions as a transcriptional activator. The recently defined target genes c-myc, cyclin D1, and matrilysin are responsible for tumor proliferation or malignant progression and explain the oncogenic potential of nuclear beta-catenin. To investigate its role in early colon carcinogenesis, we analyzed the expression of beta-catenin, its target gene c-myc, and the proliferative activity in 88 colorectal adenomas of varying size and grade of dysplasia. The results revealed i) the most significant correlation of nuclear beta-catenin and c-myc expression was not with the grade of dysplasia but with the size of the colon adenoma; ii) perfect correlation of nuclear beta-catenin and c-myc expression; iii) no significant correlation of adenoma size with the proliferative activity; and iv) no significant correlation of proliferative activity and the nuclear expression of beta-catenin and c-myc. These results imply that APC mutations have additional beta-catenin-independent functions; APC mutations alone are not sufficient for nuclear overexpression of beta-catenin; and nuclear beta-catenin has additional important functions for exceeding a threshold tumor size.

Relationship of vascular maturation in breast cancer blood vessels to vascular density and metastasis, assessed by expression of a novel basement membrane component, LH39

Angiogenesis, the formation of new vessels, has been demonstrated to be an indicator of prognosis in breast cancer patients. The extent of differentiation of the tumour vessels may affect access of peripheral white cells and egress or invasion of tumour cells. This has not been assessed in relation to tumour microvessel density or other variables and may be a marker of vascular remodelling. LH39 is a monoclonal antibody recognizing an epitope located at the lamina lucida of mature small veins and capillaries but not in newly formed vessels. To study vascular differentiation in breast tumours, we examined the vascular maturation index (VMI) in 12 normal and 50 breast carcinomas and this was correlated with different clinicopathological variables including angiogenesis. Mature vessels were defined by staining with antibodies to both LH39 and to CD31, using double immunohistochemistry, whereas immature vessels stained only for CD31. VMI was defined as the % fraction of mature vessels (LH39-positive) / total number of vessels (CD31-positive). The VMI was significantly higher in normal (54-68.5%; median 66.5%) than in tumours (0-47%; median 8.8%) (P = 0.0005). There was a significant inverse correlation between the tumour VMI and nodal status (Fisher's exact test, P = 0.01) and between high VMI and low thymidine phosphorylase (TP) expression (Mann-Whitney U-test, P= 0.01). No significant association between VMI and tumour size, oestrogen receptor, epidermal growth factor receptor, grade, angiogenesis, patient age, or E-selectin was seen. There was a significant reduction in relapse-free survival (P = 0.01) with high angiogenesis. These findings show that the VMI gives new information on the mechanism of tumour angiogenesis independently from microvessel quantitation, there is a wide variation in the differentiation of tumour vasculature but the degree of capillary differentiation is not associated with quantitative angiogenesis. The VMI identifies a subset of patients who have a high chance of regional node involvement.

Diffuse reflectance spectroscopy of human adenomatous colon polyps in vivo

Diffuse reflectance spectra were collected from adenomatous colon polyps (cancer precursors) and normal colonic mucosa of patients undergoing colonoscopy. We analyzed the data by using an analytical light diffusion model, which was tested and validated on a physical tissue model composed of polystyrene beads and hemoglobin. Four parameters were obtained: hemoglobin concentration, hemoglobin oxygen saturation, effective scatterer density, and effective scatterer size. Normal and adenomatous tissue sites exhibited differences in hemoglobin concentration and, on average, in effective scatterer size, which were in general agreement with other studies that employ standard methods. These results suggest that diffuse reflectance can be used to obtain tissue information about tissue structure and composition in vivo.

A quantitative analysis of vascularization and perfusion of human glioma xenografts at different implantation sites

The effect of tissue site of implantation of four different human gliomas on tumor vascularity and perfusion was examined. Vascular parameters of gliomas implanted subcutaneously in the nude mouse and intracerebrally in the nude rat were analyzed. Tumor vessels were stained with an antibody to collagen type IV and perfusion was investigated with the perfusion marker Hoechst 33342. Characteristic vascular patterns were observed in both intracerebral and subcutaneous xenografts belonging to the same tumor line. Major differences in vascular architecture and in the degree of vascularization were noted in comparisons of the two implantation sites for the same tumor line. Tumor perfusion was highly variable for both locations of tumor growth. Distinct differences between the implantation sites of similar tumor lines in vascular perfusion, intervascular distance, and vascular density were present. Incomplete perfusion of vascular structures, as seen in this study, may result in reduced delivery of oxygen to tumor areas. Therefore, measurements of vascular density and intervascular distance alone, without knowledge of the perfusion status, may not be sufficient to estimate the degree of tumor oxygenation. Furthermore, differences in vascular parameters may have important consequences for treatment modalities such as radiotherapy and chemotherapy. Thus, the findings in our study suggest that care has to be taken in extrapolating therapy results obtained with subcutaneous glioma tumor models to the original growth location of gliomas, the brain, due to major differences in vasculature.

Ultrastructural interactions in the microvasculature of human endometrial adenocarcinoma

OBJECTIVES

Our purpose was to study the ultrastructural morphology of the microvasculature of human endometrial adenocarcinoma and to determine the effect of this malignancy on cell-to-cell communication between the components of the microvasculature and with the other tissue compartments of human endometrium. Methods. Multiple cases of human endometrial adenocarcinoma were studied and graded by light microscopy. Six cases of Grade I and six cases of Grade II were selected. Two blocks per case were studied ultrastructurally.

RESULTS

In contrast to our expectation that the ultrastructure of tumor vessels would suggest a great deal of proliferation and new vessel formation, we found that tumor vessels displayed a high degree of cellular differentiation, in the form of numerous and varied cell-to-cell contacts, and large amounts of protein production.

CONCLUSIONS

The morphology of the microvasculature of endometrial adenocarcinoma suggests an active rather than passive role in tumor vessels.

Distribution of newly formed vessels in human colorectal carcinomas with microangiography

OBJECTIVES

 Together, tumour cells and blood vessels compose a highly integrated ecosystem. This study was designed to investigate the distribution of newly formed vessels and the relationship of tissue structure to vascularity in human colorectal carcinomas.

SUBJECTS AND METHODS

 Microangiography, a silicone rubber compound injection method, was used successfully to study 18 resected colon cases. Vascular densities were evaluated by soft x-ray examination, and histological constitution was assessed by an ocular, square lattice, superimposing technique.

RESULTS

 On average, vascular density was 1.43 times greater (range 1.02-1.80) in tumour tissue than in normal mucosa. However, the vascular density in mucinous adenocarcinomas was significantly lower than that in well and moderately differentiated adenocarcinomas. When vascular densities were compared in an upper peripheral region (UR) and a lower central region (LR) (designated as upper and lower with reference to their position in relation to the submucosal vessels), the UR showed significantly higher vascular density than the LR. Histologically, the UR had a significantly higher density of carcinoma cells than the LR.

CONCLUSION

 These results suggest that the vascularity of colorectal carcinomas varies with respect to their topographical position and their histological subtypes.

Inhibition of tumor growth and microvascular angiogenesis by the potent angiogenesis inhibitor, TNP-470, in rats

The antiangiogenic effects of TNP-470 on the neovascularization of tumors were studied by examining ultrastructural alterations in the vasculature and interstitial fluid pressure (IFP) of tumors. Wistar rats were first inoculated subcutaneously (s.c.) with the Walker 256 carcinosarcoma cell line, then either vehicle medium or TNP-470, 30 mg/kg, was injected s.c. on day 1. A tumor growth assay, the necrotic area, and the IFP in the tumor were all measured on day 12. The antiangiogenic effects of TNP-470 were studied by scanning electron microscopic images of tumor vascular casts. TNP-470 was observed to inhibit tumor growth and increase the necrotic area significantly. In the TNP-470-treated group, the IFP in the superficial layer, defined as 2-3 mm from the tumor capsule, and in the deep layer, defined as 8-10 mm from the tumor capsule, were significantly higher than the corresponding values in the control. Moreover, vascular casts showed a significant reduction in the budding of sprouts in the superficial layer, and a decrease in the maximum diameter of the tumor vessels in the deep layer. It is possible that the higher IFP in the TNP-470-treated tumors might have prevented tumor vessel dilation. The findings of this study demonstrated that TNP-470 inhibited the budding of tumor vessel sprouts, and increased the IFP. These processes seem to act synergistically to suppress tumor angiogenesis.

The microcirculation of choroidal and ciliary body melanomas

The microcirculation of ciliary body and choroidal melanomas is remodelled into patterns. The presence of microvascular networks, composed of back-to-back loops that encircle microdomains of tumour, and parallel vessels with cross-linking, are associated with death from metastatic melanoma. The formation of these complex vascular patterns may result from reciprocal interactions between the tumour cell and the extracellular matrix, and pattern formation may reflect an invasive tumour cell phenotype. Ciliary body and choroidal melanomas are among the few forms of cancer treated before a pathologist assigns a grade to indicate whether tumour is likely to follow a benign or aggressive course. There is evidence to suggest that prognostically significant microcirculatory patterns may be detectable by non-invasive imaging techniques that may provide a substitute for biopsy to guide the clinical management of patients with these sight- and life-threatening tumours.