Optimal route of administration of mixed endothelin receptor antagonist (TAK-044) in liver transplantation

A systematic review of pharmacological treatment options used to reduce ischemia reperfusion injury in rat liver transplantation

BACKGROUND

Although animal studies models are frequently used for the purpose of attenuating ischemia reperfusion injury (IRI) in liver transplantation (LT), many of pharmacological agents have not become part of clinical routine.

METHODS

A search was performed using the PubMed database to identify agents, from which 58 articles containing 2700 rat LT procedures were selected. The identified pharmacological agents were categorized as follows: I - adenosine agonists, nitric oxide agonists, endothelin antagonists, and prostaglandins, II - Kupffer cell inactivator, III - complement inhibiter, IV - antioxidant, V - neutrophil inactivator, VI -anti-apoptosis agent, VII - heat shock protein and nuclear factor kappa B inducer, VIII - metabolic agent, IX - traditional Chinese medicine, and X - others. Meta-analysis using 7-day-survival rate was also performed with Mantel-Haenszel's Random effects model.

RESULTS

The categorization revealed that the rate of donor-treated experiments in each group was highest for agents from Group II (70%) and VII (71%), whereas it was higher for agents from Group V (83%) in the recipient-treated experiments. Furthermore, 90% of the experiments with agents in Group II provided 7-day-survival benefits. The Risk Ratio (RR) of the meta-analysis was 2.43 [95% CI: 1.88-3.14] with moderate heterogeneity. However, the RR of each of the studies was too model-dependent to be used in the search for the most promising pharmacological agent.

CONCLUSION

With regard to hepatic IRI pathology, the categorization of agents of interest would be a first step in designing suitable multifactorial and pleiotropic approaches to develop pharmacological strategies.

Two-stage optical system for colorectal polyp assessments

BACKGROUND AND AIMS

Macroscopic real-time evaluations of the histopathology and degree of invasion of colorectal polyps help to select the most suitable endoscopic treatment method. Dual-focus (DF) narrow-band imaging (NBI) is a new imaging enhancement system that uses digital and optical methods to enhance the view of blood vessels on mucosal surfaces. However, the superiority of this technique over standard imaging techniques has not been previously reported. The aim of this study was to determine whether the two-stage optical systems in a new generation of endoscopes will increase the diagnostic accuracy of colorectal polyp recognition.

METHODS

The study included 270 patients, and 386 colorectal polyps were diagnosed and removed. The polyps were assessed with white light and NBI using one- and two-stage optical systems, respectively. After being classified according to the Kudo pit pattern schemes, the polyps were removed and histopathologically verified.

RESULTS

Regarding non-neoplastic lesions (Kudo I and II), no difference was observed in the recognition of polyps when using the NBI-DF function. We observed improved accuracy in the preliminary diagnoses of Kudo IIIL lesions (from 87.16 to 90.09%, p < 0.05) and Kudo IIIS lesions (from 87.29 to 92.79%, p < 0.01). NBI-DF also increased the accuracy of preliminary diagnoses of Kudo IV lesions (from 88.24 to 94.12%, p < 0.01). The Kudo V pit patterns were also more distinct with NBI-DF imaging, increasing the diagnostic accuracy from 91.67 to 100%.

CONCLUSIONS

Using a two-stage optical system with electronic colorization of the mucosa increased diagnostic accuracy for differentiating colorectal polyps with neoplastic potential.

Effectiveness of intraportal prostaglandin E1 administration after liver transplantation

PURPOSE

Prostaglandin E1 (PGE1) has been used to improve hepatic blood flow and to reduce ischemia reperfusion injuries of allografts in liver transplantation. However, PGE1 undergoes extensive metabolic clearance in the pulmonary and splanchnic circulation during intravenous administration. We analyzed the effect of intraportally administered PGE1.

METHODS

Sixty living-donor liver transplant recipients received continuous infusions of PGE1 for 10 days immediately after the reperfusion of the allografts. Of them, 40 recipients received PGE1 intravenously (IV group) via the internal jugular vein, and 20 recipients received PGE1 intraportally (IP group) through a catheter in the inferior mesenteric vein. Data were collected for 3 weeks postoperatively.

RESULTS

The IP group exhibited lower initial aspartate aminotransferase and alanine aminotransferase levels compared with the IV group. However, no apparent differences were recognized in the serum albumin, total bilirubin, alkaline phosphatase, r-glutamyl transpeptidase, or prothrombin time levels between the 2 groups. Chylorous ascites were observed more frequently in the IP group. There was no difference in portal venous flow measured by Doppler sonogram between the 2 groups during the first postoperative week.

CONCLUSION

This study demonstrated that intraportal administration of PGE1 had a better cytoprotective effect against hepatocellular damage than intravenous administration, although it did not have additional benefits for perihepatic hemodynamics.

Evaluation of new subclassification of type V(I) pit pattern for determining the depth and type of invasion of colorectal neoplasm

BACKGROUND

Colorectal neoplasms with a type V(I) pit pattern include various lesions, such as adenomas, intramucosal cancers, and submucosal carcinomas.

METHODS

We analyzed 96 colorectal neoplasms with a type V(I) pit pattern and identified six different variants: (1) unclear outline of the pit; (2) irregular margins of the pit; (3) narrowing of the pit; (4) ragged array of the pit; (5) high residual density of the pit; (6) abnormal branching of the pit. We examined the relationship between the appearance of each V(I) pit pattern and histology, including the depth of invasion.

RESULTS

In univariate logistic regression analysis the unclear outline, irregular margins, and narrowing of the pit were significantly associated with a submucosal (SM) invasion ≥1000 μm (P < 0.01). In multivariate logistic regression analysis, unclear outline of the pit was shown to be the only significant predictor of highly invasive submucosal cancer (odds ratio = 24.20, P < 0.0001). Regarding tumor morphology, the following were significantly associated with an SM invasion ≥1000 μm: in protruded type, ragged array (P = 0.022), irregular margins of the pit (P = 0.011), and unclear outline of the pit (P < 0.01); in flat type, irregular margins of the pit (P < 0.01) and unclear outline of the pit (P < 0.01); and in the depressed type, narrowing of the pit (P = 0.015) and unclear outline of the pit (P < 0.01).

CONCLUSIONS

Subclassification of the type V(I) pit pattern is useful for determining the depth of invasion of colorectal neoplasms.

Characterization of colorectal tumors using narrow-band imaging magnification: combined diagnosis with both pit pattern and microvessel features

OBJECTIVE

We aimed to clarify the clinical usefulness of narrow-band imaging (NBI) magnification for evaluating both pit appearances and microvessel architecture in comparison with evaluation of microvessel architecture alone in invasion depth of colorectal tumors.

MATERIAL AND METHODS

A total of 189 colorectal lesions [37 adenomas, 73 intramucosal to scanty submucosal invasive carcinomas and 79 massive submucosal invasive (SM-m) carcinomas] were analyzed. All lesions showing irregular pit structure were observed by NBI magnifying endoscopy. Based on both pit appearance and microvessel features, lesions were classified into three grades (C1, C2, C3), as described previously. Also, lesions were classified as high or low by microvessel irregularity. Furthermore, the histopathological background and the inter- and intraobserver variability of C subtype were assessed.

RESULTS

The SM-m rate of C1, C2 and C3 was 5.2, 60.5 and 92.7%, respectively. On the other hand, SM-m rate of lesion with mildly and highly irregular vessels was 13.3 and 55.0%, respectively. For the histopathological background, a high percentage of destruction of the glandular orifice, disappearance of the lamina muscularis mucosae and superficial exposure of desmoplastic reaction (DR) were observed in type C3. For C subtype classification of NBI magnification findings, the kappa value for interobserver variability was 0.749, and the kappa value for intraobserver variability was 0.745.

CONCLUSIONS

NBI magnification findings evaluated by both pit appearances and microvessel features (C subtype) showing a good kappa value in variability are more useful in invasion depth diagnosis of colorectal tumor than those evaluated by microvessel features alone.

Role of Fuji intelligent chromo endoscopy in observation of pit pattern and blood capillary form of colonic lesions

AIM: To compare Fuji intelligent chromo endoscopy (FICE) and staining techniques in differential diagnosis for colonic tumor and non-tumor lesions.

METHODS: From March 2007 to May 2008, 245 patients with colon neoplasm or polypoid lesions were included. The patients underwent a magnifying ordinary colonoscopy, a magnifying FICE technique and magnifying staining technique. The pit pattern and blood capillary form of the lesions were examined, an endoscopic diagnosis was made and compared with the pathologic diagnosis.

RESULTS: A total of 480 neoplasms were detected in 245 patients. There was significant difference in detecting lesions between conventional magnifying endoscopy and FICE larger models (90.0% vs 98.8%, P < 0.01). FICE magnifying endoscopy better revealed mucosal structure of capillaries than staining magnifying endoscopy (P < 0.01), but there was not significant difference in revealing duct openings. FICE showed higher coincidence rate of diagnosis, higher sensitivity and specificity of the colorectal cancer than staining techniques (92.2% vs 81.0%, 95.3% vs 85.6%, 88.4% vs 75.6%, all P < 0.01).

CONCLUSION: FICE operates easily with higher coincidence rate of diagnosis and has a satisfactory clinical practical value in diagnosing colonic cancers.

Examination of normal intestine using confocal endomicroscopy

BACKGROUND AND AIM

Endoscopy is an important clinical tool for the diagnosis and treatment of gastrointestinal disorders. However, biopsy tissue is still required in many cases to obtain a definitive histopathological diagnosis. The aim of this study was to evaluate confocal endomicroscopy (CEM) as a tool for conducting virtual biopsies of the colon by comparing CEM images with biopsy samples from normal colon.

METHODS

The study cohort comprised 45 patients who underwent investigative colonoscopy between April 2004 and January 2006, 25 of whom also had biopsy due to suspected diseases such as inflammation and neoplasm. The small and large intestine were examined with CEM using an intravenous injection of fluorescein, and CEM images were compared with conventional histopathological results from biopsied samples. In addition, the injected fluorescein was localized immunohistochemically to further analyze the CEM images taken in vivo.

RESULTS

A total of 46 biopsies were taken, of which 24 demonstrated no histopathological abnormality and were regarded as normal. All of the CEM images observed from the surface to the deeper layers were concordant histopathologically with the biopsy results. Furthermore, CEM allowed observation of physiological functions such as blood flow in the capillaries of the surrounding crypts and mucus release from crypts. The immunohistochemical localization of fluorescein was consistent with the CEM images.

CONCLUSIONS

CEM provides endoscopists with a valuable new diagnostic tool, not only for observing tissue in situ at the histopathological level, but also for the coincident evaluation of physiological function during endoscopic examination.

Hepatic effects of influxed endothelin-1 from portal vein: in situ portal vein infusion model using dogs

BACKGROUND/PURPOSE

Endothelin-1 is a potent vasoconstrictor formed by vascular endothelium. This study was designed to investigate the hepatic effect of endothelin-1 produced by portal vascular endothelium.

METHODS

Portal venous pressure, portal venous flow, hepatic arterial flow, tissue blood flow, and tissue oxygen pressure were measured during portal vein endothelin-1 infusion in dogs at rates of 1.0 to 5.0 ng/kg per minute. Sinusoidal width during maximal infusion was determined morphometrically. Serum concentrations of mitochondrial glutamic oxaloacetic transaminase and endothelin-1 in portal and hepatic venous blood were also measured.

RESULTS

Intraportal endothelin-1 infusion dose-dependently increased portal venous pressure and reduced portal venous and hepatic arterial blood flow. Tissue blood flow and oxygen pressure also decreased. Endothelin-1 also significantly increased serum mitochondrial glutamic oxaloacetic transaminase and constricted hepatic sinusoids. These changes reversed after completion of infusion.

CONCLUSIONS

Intraportal endothelin-1 caused circulatory and histological changes in hepatic sinusoids that may suggest the role of endothelin-1 formed by portal venous bed epithelium.

Effect of endothelin antagonist (TAK-044) on cerebral ischemic volume, oxidative stress markers and neurobehavioral parameters in the middle cerebral artery occlusion model of stroke in rats

Stroke causes brain injury in millions of people world wide each year. Despite the enormity of problem, currently there is no established therapy, which can restore the blood flow at infracted area and also improve the neurological deficit. The present study was carried out to investigate the effect of an endothelin antagonist (TAK-044) in middle cerebral artery (MCA) occlusion model of acute ischemic stroke in rats. Male Wistar rats were pretreated with TAK-044 (5 mg/kg, i.p.) for 7 days and thereafter subjected to focal ischemia by occlusion of MCA using intraluminal thread for two hours. 30 min after reperfusion the animals were subjected to diffusion-weighted imaging (DWI) for assessment of protective effect. Twenty-four hours later the motor performance was tested and subsequently the animals were sacrificed for estimation of markers of oxidative stress; malondialdehyde (MDA), glutathione (GSH) and superoxide dismutase (SOD). Control group received vehicle (saline) and similar experimental protocol was followed. In the TAK-044 pretreated group, percent hemispheric lesion area (% HLA) in DWI was significantly attenuated 17.5 +/- 0.5% as compared to control group 61.2 +/- 5.9%. Significant motor impairment, with significant elevated levels of MDA, decrease in GSH and SOD were observed in the vehicle treated MCA occluded rats. Pretreatment with TAK-044 prevented the motor impairment and significantly reversed the changes in markers of oxidative stress (MDA, GSH and SOD). In addition to well-known vasodilatory effect, TAK-044 has recently been documented to have antioxidant and anti-inflammatory properties. These effects can contribute to the protection afforded by TAK-044 in the present study.

Magnifying colonoscopic features of ulcerative colitis reflect histologic inflammation

BACKGROUND

Colonoscopy plays an important role in the diagnosis of ulcerative colitis and the determination of disease activity. Standard colonoscopic findings, however, do not often agree with histologic findings. The aim of this study was to clarify the relation between magnifying colonoscopic features and histologic inflammation in the course of ulcerative colitis.

METHODS

We performed magnifying colonoscopy examinations in 60 patients with ulcerative colitis. We classified the features into six types and analyzed the relations among these features, standard colonoscopic features (Matts grades), and pathohistological findings.

RESULTS

It was difficult to distinguish the remission stage from the active stage by standard colonoscopy in cases of Matts grade 2 disease. There was a relation, however, between the magnifying colonoscopic types and the degrees of histologic inflammation. The magnifying colonoscopic types reflected histologic inflammation status more accurately than did standard colonoscopic findings.

CONCLUSION

Magnifying colonoscopy is useful for determining the degree of histologic change without biopsy in patients with ulcerative colitis.

Clinicopathologic features and endoscopic resection of early primary nonampullary duodenal carcinoma

Early primary nonampullary duodenal carcinoma is an extremely rare disease with poorly defined clinicopathologic features; early detection of this carcinoma is not common. To clarify the clinicopathologic characteristics of early primary nonampullary duodenal carcinoma and retrospectively analyze methods of treatment. Seventeen early duodenal carcinomas identified between 1994 and 2001 in 15 patients were studied. Lesions were divided into 2 groups: sporadic carcinoma (10 cases in 10 patients) and familial adenomatous polyposis associated carcinoma (7 cases in 5 patients). Clinicopathologic features and methods of treatment were compared between groups. The mean age of patients with sporadic carcinoma (63.8 years) was significantly higher than that of patients with FAP-associated carcinoma (34.9 years). The incidence of sporadic carcinoma was significantly higher in men that in women (M:F ratio 9:1); the difference between sexes in the incidence of FAP-associated carcinoma (1:4) was not significant. There was no significant difference between both groups in relation to tumor size, location, gross appearance, or histopathology. Thirteen of the duodenal tumors were treated by endoscopic mucosal resection (EMR), two by polypectomy, and two by open surgery. Complications were encountered in 1 of 15 cases (6%); local bleeding occurred after one EMR, but hemostasis was achieved endoscopically. The mean follow-up period for all patients was 51.7 months. No patients experienced recurrence after resection. The significant differences between patients with sporadic and those with early FAP-associated duodenal carcinoma were in age and sex. Endoscopic resection appears to be a safe and efficient treatment of carefully selected patients with early primary nonampullary duodenal carcinoma.

Endothelin(A) receptor blockade reduces ischemia/reperfusion injury in pig pancreas transplantation

OBJECTIVE

The effect of prophylactic administration of a selective endothelin(A) receptor antagonist (ET(A)-RA) on ischemia/reperfusion injury in an experimental model of graft pancreatitis after pancreas transplantation was evaluated.

SUMMARY BACKGROUND DATA

It is well established that endothelin-1 (ET-1), a powerful vasoconstrictor, plays an important role in the development of pancreatitis. Recent studies have shown a beneficial effect of endothelin receptor antagonists in the therapy for experimental pancreatitis.

METHODS

Relevant ischemia/reperfusion injury was induced in pig pancreas transplants after 6 hours hypothermic preservation in University of Wisconsin solution. The recipients were randomized into 2 groups: control pigs received isotonic saline and the treated group received the selective ET(A)-RA BSF 208075 at the beginning of reperfusion. On postoperative days 2 and 5, animals were relaparotomized to obtain tissue specimens. Blood monitoring included lipase, amylase, C-reactive protein, trypsinogen-activation peptide, thiobarbituric acid-reacting substances, and ET-1. Partial oxygen tension (p(ti)O(2)) was measured by a Clarke-type electrode and blood flow by laser doppler. A semiquantitative score index was used for assessment of histologic injury and for immunohistochemical analysis of ET-1 and ET(A) receptor expression. Tissue mRNA levels of prepro ET-1, ET(A) receptor, pro-interleukin (IL)-6, and pro-IL-1beta were quantified using TaqMan real-time reverse transcription-polymerase chain reaction (RT-PCR).

RESULTS

Prophylactic treatment with ET(A)-RA significantly reduced the severity of graft pancreatitis evidenced by C-reactive protein. The finding of transient capillary perfusion at the beginning of reperfusion supports the application of the ET(A)-RA during this period. The dramatic increase of plasma ET-1 in the therapy group is a clear evidence of effective receptor blockade. Mean trypsinogen-activation peptide levels from the portal venous effluent, but not mean systemic plasma TAP values were significantly lower in the treated group. Analysis of p(ti)O(2) and blood flow revealed a significant improvement of capillary perfusion and blood flow in the treated group and was associated with relevant reduction of tissue injury. Intrapancreatic ET-1 and IL-6 mRNA expression and ET-1 protein levels were significantly lower in the therapy group as compared with the control group. In contrast, ET(A) mRNA showed a marked up-regulation by ET(A) receptor blockade.

CONCLUSION

Application of a ET(A)-RA reduces ischemia/reperfusion induced graft pancreatitis in a pig transplantation model by improving microcirculation and reducing tissue injury.

Gasless video endoscopic transanal excision of rectal tumors incompletely removed by colonoscopic snare polypectomy

BACKGROUND

This report describes an experience with gasless video transanal endoscopic microsurgery (VTEM) to excise rectal tumors previously incompletely removed with colonoscopic snare polypectomy.

METHODS

Gasless VTEM involves a modification of transanal endoscopic microsurgery (TEM) that incorporates a standard laparoscopic video camera and requires no CO(2) insufflation system. Nineteen patients who had had a rectal tumor removed incompletely by colonoscopic polypectomy with a diathermy snare were enrolled in this prospective study. The patients included 14 men and 5 women whose median age was 63.5 (range, 49-83) years. The rectal tumors included 4 adenomas, 11 adenocarcinomas (Tis, 7; T1, 4), and 4 carcinoid tumors. The median distance from the tumor margin to the dentate line was 5.8 (range, 2.0-13.0) cm.

RESULTS

All rectal lesions were successfully removed by gasless VTEM. No intraoperative complication occurred. The median operating time and blood loss were 40 (range, 15-145) minutes and 5 (range, 0-100) mL, respectively. The median maximal tumor diameter in 9 patients with residual tumors was 1.3 (range, 0.5-2.5) cm. There was no operative mortality. A postoperative complication (bleeding from a suture wound and transient incontinence) developed in 1 (5.3%) of the 19 patients. The median postoperative hospital stay was 5 (range, 2-10) days. Postoperative histology revealed a residual tumor in 10 (52.9%) of the 19 specimens. Complete excision of all tumors was confirmed histologically. During a median follow-up period of 59.5 (range, 12.3-94.9) months, no tumor recurred.

CONCLUSIONS

Gasless VTEM is useful and minimally invasive for the local removal of rectal tumors incompletely resected by colonoscopic snare polypectomy.

Angiogenesis at the site of deepest penetration predicts lymph node metastasis of submucosal colorectal cancer

PURPOSE

Intratumor microvessel count has been reported as a useful prognostic factor in patients with cancer of various organs. This study was undertaken to clarify the relation between microvessel count and lymph node metastasis in submucosal colorectal cancer.

METHODS

Microvessel count was estimated in 254 invasive tumors that had been resected from patients with submucosal colorectal cancer. Immunohistochemistry with antibodies against CD34 was performed on archival specimens, and microvessel counts were estimated based on the average count of three fields (original magnification, x400) in the most vascular area at the site of deepest submucosal penetration.

RESULTS

Microvessel count ranged from 10 to 98, with a median of 40. Lesions with high microvessel counts (> or =40) had a significantly higher incidence of lymph node metastasis than those with low microvessel counts (<40; 21.8 percent vs. 6.2 percent). None of the 79 lesions with low microvessel counts and submucosal invasion up to a depth of 1,500 microm had metastasized to the lymph nodes. In multivariate analysis, microvessel count was an independent risk factor for lymph node metastasis in submucosal colorectal cancer (P = 0.0026).

CONCLUSION

Microvessel count at the site of deepest submucosal penetration can be one of the most useful predictors for lymph node metastasis. Analysis that combines microvessel count and depth of submucosal invasion may predict the occurrence of lesions without lymph node metastasis.