Massive gastrointestinal bleeding due to the rupture of arterial aneurysm in Behçet's disease: case report and literature review

Massive gastrointestinal bleeding is a very rare manifestation of gastrointestinal Behçet's disease, mainly from the gastrointestinal mucosal lesions. We report herein the case of a 50-year-old man with intestinal Behçet's disease who suffered massive hemorrhage from ruptured arterial aneurysm. Colonoscopy demonstrated large amount of fresh blood in the entire colon, but we were not able to localize bleeding focus anywhere in the colon. Angiography was performed and it revealed that a small aneurysm on the right ileocolic artery with apparent extravasation of contrast material. A guiding catheter was inserted to a right ileocolic artery and superselective arterial embolization using microcoils was successful. Following this procedure, the gastrointestinal bleeding gradually subsided and completely stopped within a few days. He is now treating with prednisolone and sulfasalazine without recurrent bleeding until now.

Use of T-Stat to predict colonic ischemia during and after endovascular aneurysm repair: a case report

As surgeons become more aggressive in treating aneurysms with endovascular techniques, traditional surgical principles of preserving internal iliac arteries and the inferior mesenteric artery have been challenged. A case is presented where the T-Stat device (Spectros Corp, Portola Valley, Calif), an optical real-time sensor approved by United States Food and Drug Administration for measuring colon ischemia, was used as an adjunctive measure to assist in the successful endovascular aneurysm repair in a patient at high risk for colon ischemia.

Pneumatosis intestinalis and portal venous gas without bowel ischemia in a patient treated with irinotecan and cisplatin

Pneumatosis intestinalis and gas within the portal venous system are findings predictive of bowel ischemia. The etiologies of these alarming radiographic signs are diverse and not all causes require emergent surgical intervention. The combination of pneumatosis intestinalis, portal venous gas, and acidosis typically portends bowel ischemia and inevitable necrosis. This case report is the first description of benign pneumatosis and portal venous gas secondary to irinotecan and cisplatin.

The angiogenesis in colorectal carcinomas with and without lymph node metastases

Many clinical trials revealed that the anti-angiogenic treatment could improve prognosis in patients with metastatic colorectal carcinomas (CRC), when added to standard chemotherapy. In this paper, we tried to find out if the microvascular density (MVD) determined with CD31, CD105 was correlated with lymph node status, and if the intensity of angiogenesis was different in right versus left colon segments. We studied 187 CRC, with and without lymph node metastases, 128 from left and 59 from right colon.

RESULTS

In the right colon, the MVD was higher in the cases where the lymph nodes did not present metastases (pN0) but also when four or more lymph nodes were involved (pN2). In the rectum and sigma, the angiogenesis presented the highest intensity in pN0 and pN1 stage (1-3 lymph nodes with metastases), decreasing in pN2 stage. In the descendent colon segment, the MVD did not present differences between the cases with and without lymph node metastases.

CONCLUSIONS

Our study reveals that the most indicated cases for antiangiogenic treatment seem to be the pN0 and pN1 cases in the rectum and sigma, respectively pN0 and pN2 cases in the right colon. We tend to believe that the angiogenesis intensity in CRC is higher in early-stages of the tumoral proliferation but it is not an increasing process, having rather an oscillating character. Therefore, the angiogenesis remains an independent prognostic and predictive factor and the antiangiogenic treatment is necessary to be individualized for each patient.

Level of arterial ligation in rectal cancer surgery: low tie preferred over high tie. A review

Consensus does not exist on the level of arterial ligation in rectal cancer surgery. From oncologic considerations, many surgeons apply high tie arterial ligation (level of inferior mesenteric artery). Other strategies include ligation at the level of the superior rectal artery, just caudally to the origin of the left colic artery (low tie), and ligation at a level without any intraoperative definition of the inferior mesenteric or superior rectal arteries. Publications concerning the level of ligation in rectal cancer surgery were systematically reviewed. Twenty-three articles that evaluated oncologic outcome (n = 14), anastomotic circulation (n = 5), autonomous innervation (n = 5), and tension on the anastomosis/anastomotic leakage (n = 2) matched our selection criteria and were systematically reviewed. There is insufficient evidence to support high tie as the technique of choice. Furthermore, high tie has been proven to decrease perfusion and innervation of the proximal limb. It is concluded that neither the high tie strategy nor the low tie strategy is evidence based and that low tie is anatomically less invasive with respect to circulation and autonomous innervation of the proximal limb of anastomosis. As a consequence, in rectal cancer surgery low tie should be the preferred method.

A variant of Buhler's arc formed by the unusually long dorsal pancreatic artery

The knowledge of anatomical variations of the vascular junction between the celiac trunk and superior mesenteric artery is surgically significant. A case of unusually long dorsal pancreatic artery that originated from the common hepatic artery and directly anastomosed with the middle colic artery thus forming a rarely reported variant of Bühler's arcade is presented (Fig. 1, Ref. 14).

Acute and chronic mesenteric ischemia

This article briefly reviews the various etiologies, presentation, and diagnosis of different types of mesenteric ischemia. Operative management techniques and the applicability of percutaneous endovascular intervention are discussed. Finally, the authors explore emerging technologies that have the potential to further improve diagnosis and treatment of this frequently lethal disease process.

Pyrrolidine dithiocarbamate prevents deleterious effects of remote ischemia/reperfusion injury on healing of colonic anastomoses in rats

BACKGROUND

Pyrrolidine dithiocarbamate (PDTC) is a low-molecular-weight thiol antioxidant and potent inhibitor of nuclear factor-kappaB (NF-kappaB) activation. It has been shown to attenuate local harmful effects of ischemia/reperfusion (I/R) injury in many organs. In recent animal studies, a delaying effect of remote organ I/R injury on the healing of colonic anastomoses has been demonstrated. In this study we investigated whether PDTC prevents harmful systemic effects of superior mesenteric I/R on left colonic anastomosis in rats.

METHODS

Anastomosis of the left colon was performed in 40 rats randomly allocated into the following four groups: (1) Sham-operated group (group I, n = 10)-simultaneously with colonic anastomosis, the superior mesenteric artery and collateral branches divided from the celiac axis and the inferior mesenteric artery were isolated but not occluded. (2) Sham+PDTC group (group II, n = 10)-identical to sham-operated rats except for the administration of PDTC (100 mg/kg IV bolus) 30 minutes prior to commencing the experimental period. (3) I/R group (group III, n = 10)-60 minutes of intestinal I/R by superior mesenteric artery occlusion. (4) PDTC-treated group (group IV, n = 10)-PDTC 100 mg/kg before and after the I/R. On postoperative day 6, all animals were sacrificed, and anastomotic bursting pressures were measured in vivo. Tissue samples were obtained for investigation of anastomotic hydroxyproline (HP) contents, perianastomotic malondialdehyde (MDA) levels, myeloperoxidase activity (MPO), and glutathione (GSH) level.

RESULTS

There was a statistically significant decrease in anastomotic bursting pressure values, tissue HP content and GSH level, along with an increase in MDA level and MPO activity in group III, when compared to groups I, II, and IV (p < 0.05). However, PDTC treatment led to a statistically significant increase in anastomotic bursting pressure values, tissue HP content and GSH level, along with a decrease in MDA level and MPO activity in group IV (p < 0.05).

CONCLUSIONS

This study showed that PDTC treatment significantly prevented the delaying effect of remote organ I/R injury on anastomotic healing in the colon. Further clinical studies are needed to clarify whether PDTC may be a useful therapeutic agent for increasing the safety of the anastomosis during particular operations where remote organ I/R injury occurs.

Endothelial cells of human colorectal cancer and healthy colon reveal phenotypic differences in culture

Antiangiogenic drugs have been used successfully for the treatment of colorectal cancer (CRC). Viable tumor endothelial cells (TEC) and normal endothelial cells (NEC) of uninvolved colon tissue of the same patient have not been available to optimize treatment strategies in vitro. Therefore, our target was to establish a protocol for the isolation of TEC and NEC. These cells were isolated with very high purity via magnetic cell sorting of tissue samples obtained from CRC and healthy colon of eight patients. TEC and NEC expressed CD31, CD105, VE-cadherin, VCAM-1, ICAM-1 and E-selectin, formed capillaries in basal membrane extract and were able to take up acetylated low-density lipoprotein. They were negative for podoplanin, CD45, CD68 and cytokeratin-20 indicating blood vessel endothelial lineage. Intense staining of von Willebrand factor (vWF) was observed in five of eight NEC cultures, whereas vWF was absent or only slightly expressed in all TEC cultures in vitro. Low intracellular concentration of vWF was also detected in TEC and NEC at the tissue level. This demonstrated that differences exhibited by TEC and NEC in vivo are stably perpetuated in culture. The isolated cultures may provide a useful in vitro model to elucidate epigenetic effects on angiogenesis in cancer and to optimize antiangiogenic therapy.

Watermelon colon: is there an association with alcohol?

BACKGROUND

Watermelon colon, or rectal vascular ectasia of the colon, is a very rare vascular lesion.

CASE REPORT

A 56-year-old male heavy drinker was admitted to hospital with hematochezia. Colonoscopy revealed linear, watermelon-like vascular stripes throughout the entire colon. Rectal biopsies confirmed the vascular nature of these lesions, showing dilated and trombosed capillaries in the lamina propria. He had neither cirrhosis nor portal hypertension. The watermelon-like lesions regressed spontaneously following the cessation of alcohol intake.

CONCLUSIONS

This observation suggests that this condition can be triggered by alcohol.

Colocutaneous fistula complicating therapeutic mesenteric embolisation

Percutaneous embolotherapy has now assumed an important role in the management of massive colonic haemorrhage. However, this therapeutic option is associated with a significant risk of irreversible segmental colonic ischaemia. We present a case where distal segmental ischaemia led to a colocutaneous fistula, a complication not reported so far in the literature.

Applied vascular anatomy of the colon and rectum: clinical implications for the surgical oncologist

Surgery remains the most radical method of treatment of many solid tumors, including colorectal cancer; in these tumors, surgery is the only method that can offer the chance of cure. To avoid early postoperative morbidity (mainly, anastomotic leak) and to achieve good long-term results (low incidence of tumor recurrence, long overall and disease-free survival, and optimal quality of life), the surgeon should have an in-depth knowledge of vascular anatomy of the colon and rectum. This essential requirement is based on the fact that the actual course followed by lymph fluid drainage from any part of the colon/rectum is determined by its blood supply; therefore, the extent of resection for colorectal cancer follows the principles of blood supply and lymphatic drainage. Knowledge of the colorectal vascular anatomy and its variations is of vital importance in the planning of radical surgical treatment and in appropriately performing colorectal resections, particularly in the patient who underwent in the past colectomy or aortic surgery that has changed the usual pattern of collateral blood supply to the colon. This review summarizes currently available data regarding vascular anatomy of the colon and rectum, from a surgical perspective.

P-selectin glycoprotein ligand-1 regulates chemokine-dependent leukocyte recruitment in colonic ischemia-reperfusion

OBJECTIVE AND DESIGN

Leukocyte recruitment is a key feature in ischemia-reperfusion (I/R) -provoked tissue injury. This study evaluated the role of P-selectin-glycoprotein ligand-1 (PSGL-1) in CXC chemokine- and ischemia-reperfusion- induced leukocyte rolling and adhesion in the colon.

MATERIALS

Balb/c mice were used in an inverted intravital fluorescence microscopy study of the microvascular bed in the colon.

TREATMENT

Mice were challenged with macrophage inflammatory protein-2 (MIP-2) intraperitonally and leukocyte-endothelium interactions were analysed 3 h later. In separate experiments, mice were exposed to I/R by clamping of the superior mesenteric artery for 30 min and leukocyte rolling and adhesion were analysed after 120 min of reperfusion.

RESULTS

MIP-2 dose-dependently increased leukocyte rolling and adhesion in the colon. Pretreatment with an anti-PSGL-1 antibody reduced MIP-2-provoked leukocyte rolling and adhesion by more than 89%. I/R increased expression of MIP-2 as well as leukocyte rolling and adhesion. Immunoneutralization of PSGL-1 decreased reperfusion-induced leukocyte rolling by 85% and adhesion by 93% in colonic venules.

CONCLUSIONS

Our data demonstrates that PSGL-1 is a dominant adhesion molecule supporting MIP-2- and I/R-provoked leukocyte rolling. Inhibition of PSGL-1 abolished leukocyte rolling and abrogated I/R-induced leukocyte adhesion in colonic venules. These findings suggest that targeting PSGL-1 may be an effective strategy to prevent I/R-induced inflammation in the colon.

The effect of remote ischemic preconditioning on healing of colonic anastomoses

BACKGROUND

We aimed to investigate the potential protective effect of remote ischemic preconditioning (IPC) on delayed colonic anastomotic healing induced by remote ischemia and reperfusion (I/R) injury.

MATERIALS AND METHODS

Forty male Wistar rats were randomly assigned into four groups, each consisting of 10 rats: the control group (C), the remote I/R group [I/R, 40 min of superior mesenteric artery (SMA) occlusion], the preconditioned I/R group (IPC, two cycles of 5 min temporary occlusion of SMA before an ischemic insult of 40 min), and the preconditioned group (PC, two cycles of 5 min temporary occlusion of SMA). Colonic anastomosis was performed immediately after the ischemic insult. Anastomotic healing was assessed on postoperative day 7 by determining anastomotic bursting pressure (ABP), tissue hydroxyproline content, histopathological examination, malondialdehyde (MDA), and nitric oxide levels.

RESULTS

Remote I/R injury resulted with significant impairment in anastomotic healing in terms of mean ABP (P = 0.004), hydroxyproline content (P = 0.002), histopathological healing score (P = 0.001), nitric oxide level (P = 0.010), and MDA levels (P = 0.0001) when compared with the control group, but remote IPC did not improve all above mentioned parameters (P = NS for all), except MDA level (P = 0.011) when compared with I/R group. PC alone impaired the ABP (P = 0.0001), but it did not significantly change the other parameters measured (P = NS).

CONCLUSIONS

The results of this study showed that remote IPC did not prevent I/R-induced delaying in colonic anastomotic healing.

Pan-colonic varices and idiopathic portal hypertension

Varices of the lower GI tract, although rare, are a known cause of hematochezia. They are usually found in a segmental distribution and are often associated with cirrhosis, portal hypertension, or portal vein obstruction. We present the case of a 43-year-old male with no personal or family history of liver disease, who experienced recurrent rectal bleeding over a 27-year period. Colonoscopy revealed varices from the rectum to the cecum confirmed with endoscopic ultrasound, while esogastroduodenoscopy, small bowel series, and CT were all normal. Portal hypertension was present without an identifiable cause.

Massive mesenteric ischemia resulting from a giant strangulated umbilical hernia

Hernia repair is the most commonly practiced operation in the departments of surgery in developed countries. Huge abdominal hernias are uncommon in western civilization. We present a rare case of a 73-year-old woman with a diagnosis at admission of intestinal obstruction caused by a giant strangulated umbilical hernia. At the clinical and radiological examination, the patient showed an enormous strangulated umbilical hernia with acute abdomen, atrial fibrillation, and pulmonary subedema. Emergency laparotomy showed a huge peritoneal umbilical sac containing massive mesenteric ischemia starting from 40 cm after the Treitz ligament and extended to the right colonic flexure. A near-total resection of the small bowel, a right colectomy with double terminal stomas, and a direct hernia repair without prosthetic mesh were performed. Twenty days after the operation, the patient was discharged and begun domiciliary total parenteral nutrition, and 24 months after surgical treatment she is still alive.

The microvascular thrombi of colonic tissue in ulcerative colitis

Mucosal microvascular thrombi in rectal biopsies were observed in some ulcerative colitis (UC). Heparin may be effective in steroid resistant UC in some studies, however, the new results of meta-analysis demonstrated a non-significant effect of heparin in controlled clinical trials, differing markedly from observational studies. The objective of this study was to identify colonic microvascular thrombi in larger cases with UC, and analyse its possible risk factors: age, gender, histologic score, extent of lesions and operation or biopsy specimens, and assess the significance of microvascular thrombosis in patients with UC. The microvascular thrombi were identified by immunohistochemical staining with anti-CD61 monoclonal antibody and Martius scarlet blue (MSB) staining in 40 colonic tissue samples of UC (31 biopsy specimens and nine operated cases) and 12 cases of normal colon tissue from operated colonic carcinoma. Logistic regression analysis was used to assess the relationship of age, gender, degree of histology, origin of the specimens, extent of lesions and microvascular thrombi examined. Microvascular thrombi were positive in 14 of 40 UC cases, and none in the controls. The presence of microvascular thrombi was related to operation specimens with odds ratio 11.667, P=0.0179, it might be also related to histologic score (OR=1.350) and extent of lesions (OR=1.619). These results suggest that microvascular thrombosis may be one of the important pathogenesis in some UC, and that the effect of anticoagulant treatment still needs to be assessed.

Ischemic necrosis of the right colon in a patient with a ventricular assist device system

Despite improvements in medical therapy, the annual high mortality rate from end-stage heart failure continues. Although cardiac transplantation is a successful treatment for these patients, the shortage of donor hearts has led surgeons to seek other options. Ventricular assist device (VAD) technology is applied to a broader population of heart failure patients, and clinicians are confronted with the specialized perioperative and chronic care of patients who receive these devices. VAD implantation is now an acceptable means of bridging to heart transplantation. We report a case of isolated right colon necrosis in a patient with VAD, who was successfully treated with right hemicolectomy and ileocolostomy.

Vascular relationships in right colectomy for cancer: clinical implications

AIMS

The study aim was to provide data on pattern and length of crossing of the ileocolic artery (ICA) and right colic artery (RCA) with the superior mesenteric vein (SMV).

METHODS

Specimens from 30 fresh human cadavers underwent corrosion casting. Methylacrylate was injected into the SMV and superior mesenteric artery (SMA). Length of crossing was measured with a scaleable ruler and copper wire. Values are mean (SD; range).

RESULTS

ICA was present in all specimens and crossed posterior to the SMV in 19 (63.33%) of 30 specimens. Length of crossing was 17.01 (7.84; 7.09-42.89) mm. RCA was present in 19 (63.33%) of 30 specimens. RCA crossed anterior to SMV in 16 (84.21%) of 19 specimens. Length of crossing was 20.63 (8.09; 6.3-35.7) mm.

CONCLUSIONS

ICA was always present, crossed posterior to SMV in 60% of specimens with a crossing length of 17 mm. RCA was present in 63% of specimens, crossed anterior to the SMV in 84% of specimens with a crossing length of 20 mm. Clinical implications include arterial length left behind with main nodes, arterial bleeding and safety of laparoscopic access.

Pharmacologically mediated colon ischemia

Colon ischemia (CI) is the most common form of ischemic injury of the gastrointestinal tract. Determining the precise incidence of CI is a challenging task, because of its often brief, mild nature, and frequent spontaneous resolution, as well as its misdiagnosis as other diseases. While many underlying disease conditions may predispose patients to CI, an important and possibly overlooked etiology is that of pharmacologically induced alterations of colonic blood flow. This review details the pharmacologic agents known to be associated with CI; when possible, their mechanisms of action are described. The aim of this paper is to highlight this often unrecognized cause of CI, thereby helping physicians to be aware of the association, to recognize its occurrence promptly, and to possibly reduce morbidity and mortality.

Passage of "colonic cast" after colorectal surgery: report of four cases and review of the literature

Anal passage of a full-thickness infarcted colonic segment (so-called "cast") not accompanied by any features of acute peritonitis is a very rare occurrence and may be the main advertising manifestation of acute colonic ischemia. Most of the reported cases of acute colonic ischemia are secondary to abdominal aortic aneurysms and ensuing inferior mesenteric artery thrombosis or to the repair of these aneurysms. The preceding events causing ischemia in other cases are Hartmann reversal, rectal resection and colonic J-pouch construction, and acute pancreatitis. In this article we present our experience on four cases of colonic cast passage, all of which developed subsequent to colorectal resection. Three of these casts are supposed to be mucosal and one is transmural. Generally, surgery is the rule and consists of the resection of the concerned ischemic segment. Every clinician should be aware of this form of presentation of bowel ischemia, not only following aneurysm surgery but also in the postoperative course of colorectal surgery.

Immmunohistochemical study of the blood and lymphatic vasculature and the innervation of mouse gut and gut-associated lymphoid tissue

The blood and lymphatic vascular system of the gut plays an important role in tissue fluid homeostasis, nutrient absorption and immune surveillance. To obtain a better understanding of the anatomic basis of these functions, the blood and lymphatic vasculature of the lower segment of mouse gut and several constituents of gut-associated lymphoid tissue (GALT) including Peyer's patch, specialized lymphoid nodules in the caecum, small lymphoid aggregates and lymphoid nodules in the colon were studied by using confocal microscopy. Additionally, the innervation and nerve/immune cell interactions in the gut and Peyer's patch were investigated by using cell surface marker PGP9.5 and Glial fibrillary acidic protein (GFAP). In the gut and Peyer's patch, the nerves have contact with B cell, T cell and B220CD3 double-positive cells. Dendritic cells, the most important antigen-presenting cells, were closely apposed to some nerves. Some dendritic cells formed membrane-membrane contact with nerve terminals and neuron cell body. Many fine nerve fibres, which are indirectly detected by GFAP, have contact with dendritic cells and other immune cells in the Peyer's patch. Furthermore, the expression of Muscarinic Acetylcholine receptor (subtype M2) was characterized on dendritic cells and other cell population. These findings are expected to provide a route to understand the anatomic basis of neuron-immune regulation/cross-talk and probably neuroinvasion of prion pathogens in the gut and GALT.

Riolan's arch: confusing, misnomer, and obsolete. A literature survey of the connection(s) between the superior and inferior mesenteric arteries

BACKGROUND

There are 2 interpretations of Riolan's arch: (1) Riolan's arch is identical to a central part of the marginal artery (MA), connecting the superior (SMA) and the inferior mesenteric (IMA) arteries; and (2) Riolan's arch represents a rare artery, connecting the SMA and the IMA. The current review aims to emphasize the clinical importance of the colon's vasculature and to show the feasibility of abolishing the terms "Riolan's arch" and "meandering mesenteric artery."

METHODS

A literature survey was performed.

RESULTS

It appears that no distinct identity can be ascribed to Riolan's arch and that the "meandering mesenteric artery" represents an angiographically hypertrophied MA and/or the ascending branch of the left colic artery. However, a rare, centrally located, communicating artery has been described. Generally, the MA is sufficient for left colic circulation after ligation of the IMA, but at the splenic flexure, patency of the ascending branch of the left colic artery can be primordial.

CONCLUSION

As connections between the SMA and the IMA can be adequately described using structures mentioned in Terminologica Anatomica, the terms "Riolan's arch" and "meandering mesenteric artery" should be abolished.

Sympathetic vasoconstrictor regulation of mouse colonic submucosal arterioles is altered in experimental colitis

Recent studies suggest that altered neural regulation of the gastrointestinal microvasculature contributes to the pathogenesis of inflammatory bowel disease. Therefore, we employed video microscopy techniques to monitor nerve-evoked vasoconstrictor responses in mouse colonic submucosal arterioles in vitro and examined the effect of 2,4,6-trinitrobenzene sulphonic acid (TNBS) colitis. Nerve stimulation (2-20 Hz) caused frequency-dependent vasoconstrictor responses that were abolished by tetrodotoxin (300 nm) and guanethidine (10 microm). The P2 receptor antagonist suramin (100 microm) or the alpha(1)-adrenoceptor antagonist prazosin (100 nm) reduced the vasoconstriction and the combination of suramin and prazosin completely abolished responses. Nerve-evoked constrictions of submucosal arterioles from mice with TNBS colitis were inhibited by prazosin but not suramin. Superfusion of ATP (10 microm) resulted in large vasoconstrictions in control mice but had no effect in mice with colitis whereas constrictions to phenylephrine (3 microm) were unaffected. P2X(1) receptor immunohistochemistry did not suggest any alteration in receptor expression following colitis. However, Western blotting revealed that submucosal P2X(1) receptor expression was increased during colitis. In contrast to ATP, alphabeta-methylene-ATP (1 microm), which is resistant to catabolism by nucleotidases, constricted control and TNBS arterioles. This indicates that reduced purinergic transmission to submucosal arterioles may be due to increased degradation of ATP during colitis. These data comprise the first description of the neural regulation of mouse submucosal arterioles and identify a defect in sympathetic regulation of the GI vasculature during colitis due to reduced purinergic neurotransmission.

Murine microvideo endoscopy of the colonic microcirculation

Natural orifice endoscopy in small animal models has been limited in the past by instrument size and optical performance. In this report, we investigate the feasibility of using a recently developed microvideo endoscopy system to evaluate the colon microcirculation. Using a murine model of acute colitis, microvideo endoscopy was useful in mapping the topography of inflammation as well as identifying relevant structures in the microcirculation. We conclude that natural orifice endoscopy is a useful method for the minimally invasive longitudinal assessment of the colonic mucosal microcirculation.

Ileocolon Graft Pedicled on Ileocolic Artery: An Alternative Esophageal Substitute for Corrosive Injury

A variety of bowel interpositions have been well-developed for esophageal replacement surgery. However the choices are often limited in the case of alimentary corrosive injury due to frequent associated injuries. Herein we present a case of caustic injury with compromised mesocolon. Successful reconstruction of the alimentary integrity was accomplished using an ileocolic graft pedicled on an ileocolic artery.

COLON ASCENDENS STENT PERITONITIS-A MODEL OF SEPSIS ADOPTED TO THE RAT

The colon ascendens stent peritonitis (CASP) procedure creates an intestinal leakage of feces, resulting in diffuse peritonitis and polymicrobial sepsis. Mouse models of CASP have been used to study sepsis experimentally. The aim of the present study was to establish CASP sepsis in rats and to provide basic functional characteristics of this model. In analogy to the mouse model, 3 degrees of severity of CASP sepsis, 2 sublethal and 1 lethal, were established depending on the stent diameter. Radio-telemetric recordings in a sublethal model showed that the nonsurvivors remained hemodynamically stable until approximately 1 h before death, when heart rate and blood pressure fell rapidly. Intestinal microcirculatory changes were analyzed 3, 6, 12, and 18 h after CASP surgery using intravital microscopy in a sublethal model. After 18 h, the numbers of the leukocytes firmly adhering to the endothelium and of the ones temporarily interacting were significantly increased. The levels of IL-6 and IL-1beta increased continuously during the CASP experiments while remaining unchanged in the sham group. TNF-alpha and IL-10 levels of CASP animals reached a maximum after 12 h. In conclusion, a rat model of CASP sepsis has been established and characterized with regard to alterations in cardiovascular and microcirculatory function as well as plasma cytokine levels. In experimental settings where genetically engineered animals are not required, it will facilitate detailed examination of dynamic changes in integrated organ function during the course of sepsis and the investigation of treatment strategies.

Impact of 5-HT3 receptor blockade on colonic haemodynamic responses to ischaemia and reperfusion in the rat

5-HT(3) receptor antagonists are clinically available for treating patients with irritable bowel syndrome (IBS) but their use is restricted because of a link with some episodes of ischaemic colitis. However, the role of 5-HT3 receptors in regulating colonic blood flow has not been systematically investigated. Thus, we examined acute and chronic treatment with alosetron, a potent and selective antagonist of the 5-HT3 receptor, on baseline colonic blood flow and haemodynamic responses during occlusion and reactive hyperaemia in the pentobarbitone-anaesthetized rat. Colonic haemodynamics were assessed using ultrasonic recordings of superior mesenteric blood flow (MBF) and laser Doppler recordings of colonic vascular perfusion (VP). Blood pressure (BP) was also monitored and in some experiments tissue oxygen was detected polarographically. Alosetron (10, 30, 100 microg kg(-1), i.v.) had no effect on baseline haemodynamics nor responses to nitric oxide synthase inhibition with N(omega)-nitro-l-arginine methyl ester (l-NAME) (16 mg kg(-1)). Arterial occlusion (5 min) reduced MBF (-98.6 +/- 0.6%) and VP (-70.7 +/- 5.4%) followed by a post-occlusion reactive hyperaemia (MBF = +94.5 +/- 19.1%; VP = +60.0 +/- 22.3%) the magnitude of which was unchanged following acute (30 microg kg(-1)) or chronic alosetron administration (0.5 mg kg(-1) twice daily, 5 days). Alosetron did not significantly alter baseline colonic blood flow in the anaesthetized rat; nor did it interfere with vascular control mechanisms activated during occlusion and reactive hyperaemia.

Tissue factor: a mediator of inflammatory cell recruitment, tissue injury, and thrombus formation in experimental colitis

There is growing evidence for an interplay between inflammatory and coagulation pathways in acute and chronic inflammatory diseases. However, it remains unclear whether components of the coagulation pathway, such as tissue factor (TF), contribute to intestinal inflammation, and whether targeting TF will blunt the inflammatory cell recruitment, tissue injury, and enhanced thrombus formation that occur in experimental colitis. Mice were fed 3% dextran sodium sulfate (DSS) to induce colonic inflammation, with some mice receiving a mouse TF-blocking antibody (muTF-Ab). The adhesion of leukocytes and platelets in colonic venules, light/dye-induced thrombus formation in cremaster muscle microvessels, as well as disease activity index, thrombin-antithrombin (TAT) complexes in plasma, and histopathologic changes in the colonic mucosa were monitored in untreated and muTF-Ab-treated colitic mice. In untreated mice, DSS elicited the recruitment of adherent leukocytes and platelets in colonic venules, caused gross and histologic injury, increased plasma TAT complexes, and enhanced thrombus formation in muscle arterioles. muTF-Ab prevented elevation in TAT complexes, reduced blood cell recruitment and tissue injury, and blunted thrombus formation in DSS colitic mice. These findings implicate TF in intestinal inflammation and support an interaction between inflammation and coagulation in experimental colitis.

Angiogenesis blockade as a new therapeutic approach to experimental colitis

BACKGROUND

Neoangiogenesis is a critical component of chronic inflammatory disorders. Inhibition of angiogenesis is an effective treatment in animal models of inflammation, but has not been tested in experimental colitis.

AIM

To investigate the effect of ATN-161, an anti-angiogenic compound, on the course of experimental murine colitis.

METHOD

Interleukin 10-deficient (IL10(-/-)) mice and wild-type mice were kept in ultra-barrier facilities (UBF) or conventional housing, and used for experimental conditions. Dextran sodium sulphate (DSS)-treated mice were used as a model of acute colitis. Mice were treated with ATN-161 or its scrambled peptide ATN-163. Mucosal neoangiogenesis and mean vascular density (MVD) were assessed by CD31 staining. A Disease Activity Index (DAI) was determined, and the severity of colitis was determined by a histological score. Colonic cytokine production was measured by ELISA, and lamina propria mononuclear cell proliferation by thymidine incorporation.

RESULT

MVD increased in parallel with disease progression in IL10(-/-) mice kept in conventional housing, but not in IL10(-/-) mice kept in UBF. Angiogenesis also occurred in DSS-treated animals. IL10(-/-) mice with established disease treated with ATN-161, but not with ATN-163, showed a significant and progressive decrease in DAI. The histological colitis score was significantly lower in ATN-161-treated mice than in scrambled peptide-treated mice. Inhibition of angiogenesis was confirmed by a significant decrease of MVD in ATN-161-treated mice than in ATN-163-treated mice. No therapeutic effects were observed in the DSS model of colitis. ATN-161 showed no direct immunomodulatory activity in vitro.

CONCLUSION

Active angiogenesis occurs in the gut of IL10(-/-) and DSS-treated colitic mice and parallels disease progression. ATN-161 effectively decreases angiogenesis as well as clinical severity and histological inflammation in IL10(-/-) mice but not in the DDS model of inflammatory bowel disease (IBD). The results provide the rational basis for considering anti-angiogenic strategies in the treatment of IBD in humans.

Laparoscopic medial-to-lateral colon dissection: how and why

Laparoscopic colectomy is a difficult procedure with a long learning curve. We describe in this study our technique for right- and left-sided laparoscopic medial-to-lateral colectomy. The medial approach involves division of the vascular pedicle first, followed by mobilization of the mesentery toward the abdominal wall, and finally freeing of the colon along the white line of Toldt. This approach allows immediate identification of the plane between the mesocolon and the retroperitoneum and renders the dissection fast and safe. Our series of 50 consecutive laparoscopic colectomies supports this concept. We believe that surgeons familiar with this technique will have an important tool in their armamentarium to circumvent some of the challenges of laparoscopic colectomy.

Endothelin-1 and pancreatic islet vasculature: studies in vivo and on isolated, vascularly perfused pancreatic islets

Endothelin-1 (ET-1) is a potent endothelium-derived vasoconstrictor, which also stimulates insulin release. The aim of the present study was to evaluate whether exogenously administered ET-1 affected pancreatic islet blood flow in vivo in rats and the islet arteriolar reactivity in vitro in mice. Furthermore, we aimed to determine the ET-receptor subtype that was involved in such responses. When applying a microsphere technique for measurements of islet blood perfusion in vivo, we found that ET-1 (5 nmol/kg) consistently and markedly decreased total pancreatic and especially islet blood flow, despite having only minor effects on blood pressure. Neither endothelin A (ET(A)) receptor (BQ-123) nor endothelin-B (ET(B)) receptor (BQ-788) antagonists, alone or in combination, could prevent this reduction in blood flow. To avoid confounding interactions in vivo, we also examined the arteriolar vascular reactivity in isolated, perfused mouse islets. In the latter preparation, we demonstrated a dose-dependent constriction in response to ET-1. Administration of BQ-123 prevented this, whereas BQ-788 induced a right shift in the response. In conclusion, the pancreatic islet vasculature is highly sensitive to exogenous ET-1, which mediates its effect mainly through ET(A) receptors.

[Terlipressin and reversible intestinal ischaemia]

The vasopressin analogue terlipressin (Glypressin) is generally considered an effective and safe treatment for acute oesophageal variceal haemorrhage. Safety is especially related to very few severe ischaemic side effects compared to those resulting from treatment with vasopressin. This case report describes reversible ischaemia in the colon and small intestine as seen by exploratory celiotomy in relation to treatment with terlipressin. The patient recovered fully without the need for intestinal resection.

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.

Incidence of colonic ischemia after repair of ruptured abdominal aortic aneurysm with endograft

BACKGROUND

Colonic ischemia after open repair of ruptured abdominal aortic aneurysm (rAAA) has been reported to be as high as 42% and is associated with high mortality rates when transmural necrosis is involved. With the evolution of endovascular aortic repair (EVAR) devices, some centers now primarily use this technique for rAAA. The objective of this study was to determine the incidence of colonic ischemia after EVAR of rAAA.

STUDY DESIGN

All patients who underwent EVAR of rAAA from January 2002 to January 2006 were included in this review. All flexible sigmoidoscopies were performed within 48 hours, ischemia was graded consistently, and treatment was initiated per protocol based on grade of ischemia. Patients with grades I and II ischemia were followed up with medical management and in some cases, repeat colonoscopy. All patients with grade III ischemia underwent bowel resection.

RESULTS

Forty-four patients underwent EVAR of rAAA during the study period. Operative mortality was 11%. Sigmoidoscopy was performed in 36 of 39 patients who survived longer than 24 hours. Bowel ischemia was documented in 8 of the 36 patients (23%). Of these, five had grade I or grade II ischemia at both initial and repeat endoscopy, so these patients did not progress to resection. Three patients underwent exploratory laparotomy with bowel resection because of grade III ischemia; one of these procedures was performed for worsening ischemia discovered at repeat colonoscopy.

CONCLUSIONS

This study demonstrated that the overall incidence of colonic ischemia (23%) after EVAR of rAAA is less than that reported for the open repair. We would continue to recommend mandatory flexible sigmoidoscopy for these patients.

Structural adaptations in the murine colon microcirculation associated with hapten-induced inflammation

BACKGROUND

Blood flowing across the vascular endothelium creates wall shear stress, dependent on velocity of flow and vessel geometry, that tends to disrupt lymphocyte-endothelial cell adhesion.

OBJECTIVE

The microcirculation in a murine model of acute colitis was investigated to identify structural adaptations during acute colitis that may facilitate transmigration.

METHODS

In 2,4,6-trinitrobenzenesulphonic acid-induced acute colitis, the infiltrating cells and colonic microcirculation was investigated by cellular topographic mapping, corrosion casting and three-dimensional scanning electron microscopy (SEM). Colonic blood velocimetry was performed using intravital microscopy.

RESULTS

Clinical and histological parameters suggested a peak inflammatory response at 96 h (p<0.001). The infiltrating cells were spatially related to the mucosal capillary plexus by three-dimensional topographic mapping (p<0.001). In normal mice, corrosion casting and three-dimensional SEM showed a polygonal mucosal plexus supplied by ascending arteries and descending veins. After 2,4,6-trinitrobenzenesulphonic acid stimulation, three-dimensional SEM showed preserved branch angles (p = 0.52) and nominal vessel lengths (p = 0.93), but a significantly dilated mucosal capillary plexus (p<0.001). Intravital microscopy of the mucosal plexus showed a greater than twofold decrease in the velocity of flow (p<0.001).

CONCLUSIONS

The demonstrable slowing of the velocity of flow despite an increase in volumetric flow suggests that these microvascular adaptations create conditions suitable for leucocyte adhesion and transmigration.

Reduced severity of a mouse colitis model with angiotensin converting enzyme inhibition

Ulcerative colitis is characterized by elevated rates of epithelial cell apoptosis, and an up-regulation of pro-apoptotic cytokines including tumor necrosis factor alpha (TNF-alpha). Recently, angiotensin converting enzyme (ACE) has been shown to promote apoptosis. In addition, pharmacologic ACE inhibition (ACE-I) both prevents apoptosis and reduces TNF-alpha expression in vitro. We hypothesized that ACE-I, using enalaprilat, would decrease colonic epithelial cell apoptosis and reduce colitis severity in the dextran sulfate sodium (DSS)-induced colitis model in mice. We assessed the severity of colitis, and colonic epithelial cell apoptosis, after administration of DSS. Mice were given either daily ACE-I treatment or daily placebo. ACE-I treatment markedly improved clinical outcomes. In addition, ACE-I treatment significantly reduced the maximum histopathologic colitis grade. ACE-I also dramatically reduced the epithelial apoptotic rate. To investigate the mechanism by which ACE-I reduced apoptosis; we measured TNF-alpha, Bcl-2, and Bax expression. TNF-alpha mRNA was significantly lower with ACE-I treatment compared to placebo at every time point, as was the ratio of Bax to Bcl-2. We conclude that ACE-I reduces the severity of DSS-induced colitis and reduces epithelial cell apoptosis.

Comparative study of the hyperbaric hyperoxygenation in ischemic colonic loops in rats

PURPOSE: To analyze and to evaluate the effect of the hyperbaric hyperoxygenation in the mechanical resistance of ischemic colon of rats. METHODS: Eighty rats, distributed in four groups of 20 animals in each one, were used. In group 1 (G1), the control group, ischemia was not caused. Group 2 was submitted to the lesser degree of ischemia. Group 3 was submitted to the intermediate degree of ischemia. In group 4, a bigger degree of intestinal ischemia was provoked. Each group was divided in two sub-groups of ten animals each: with hyperbaric chamber (CC) and without hyperbaric chamber (SC). The animals of the four CC subgroups were placed in an experimental hyperbaric chamber in order to inhale oxygen at 100%, at two Absolute Atmospheres, for 120 minutes, for a four-day consecutive period. The animals of the four SC subgroups were kept in environment air during the five days of the experiment. All animals have been submitted to the mechanical study of the intestinal loop by the pressure test of the rupture by liquid distension. The euthanasia occurred in the fifth post-operative day. RESULTS: Considering the ischemia factor, the four groups were different among them (p=0.0001). There was no statistical difference between subgroups CC and SC (p=0.3461). CONCLUSION: The hyperbaric oxygen-therapy did not present improvement on the induced ischemia in rats upright colic loop.

Nonmyeloablative stem cell therapy enhances microcirculation and tissue regeneration in murine inflammatory bowel disease

BACKGROUND AND AIMS

Reduced microcirculation has been implicated in the pathogenesis of inflammatory bowel disease (IBD). Stem cells or endothelial progenitor cells are thought to contribute to tissue regeneration through neoangiogenesis or vasculogenesis in ischemia- or inflammatory-related diseases. We therefore hypothesized that adult stem cells facilitate epithelial repair in IBD.

METHODS

Moderate-severe colitis in mice was induced by dextran sulfate sodium (DSS) and 2.0 x 10(6) immortalized CD34(-) stem cells infused twice via the tail vein during an observation period of 35 days in a nonmyeloablative setting.

RESULTS

Here, we demonstrate that adult stem cells home to the damaged digestive tract in the large intestine and facilitate mucosal repair in moderate-severe colitis. Nonmyeloablative stem cell therapy resulted in increased survival in severe colitis (P < .0001). Moreover, clinical activity and histologic evaluation of the colitis severity score were reduced significantly in moderate (P = .0003 or P = .03) and severe (P < .0001 or P < .03) colitis after 35 days, in addition to the DSS-induced shortening of colon length (P = .002 and P < .0002). Genetically marked stem cells were detected predominantly in the submucosa of the damaged colon epithelium. Epithelial repair in experimental IBD was mediated either by induction of improved vasculogenesis or by the differentiation of the transplanted stem cells into endothelial cells, as demonstrated by the promotion of Tie2 activity in the infused cells at the site of the damaged mucosa.

CONCLUSIONS

Our findings indicate that systemically administered adult stem cells respond to an adequate tissue lesion in murine IBD by enhancing microcirculation, resulting in accelerated tissue repair.