Features of chronic allograft rejection on rat small intestine transplantation

The aim of this study was to develop a model of chronic rejection of the entire small intestine transplantation and to analyze the features of chronic rejection. Allogenic small bowel transplantation was performed in a rat combination of Lewis to F344. Intestines were procured at the 60th and the 90th day after operation. We compared the semiquantitative score of histological parameters. The immunological components involved in the chronic rejection process were evaluated by immunohistochemical staining and the cytokine levels in grafts. The significant characteristics of the allograft on histology were changes of villous architecture, interstitial fibrosis, leukocyte infiltration, and obliterative arteriopathy. Allografts on the 60th day post-transplantation had more score in inflammatory events, while the grafts on the 90th day after operation had more values in ischemia/fibrotic events. The number of infiltrating CD4, CD8 and macrophage cells in allografts progressively decreased over time. The level of intragraft cytokines such as IL-6, TNF-alpha and IL-10 in the 90th day after transplantation also decreased compared with that in the 60th day. These data suggested that in the early stage (POD 60), there were more active and intense inflammatory events; later (POD 90) allografts manifested less inflammation and more arterial obliteration and fibrosis.

Visceral Artery Aneurysms

OBJECTIVE

Visceral artery aneurysms are rare vascular malformations and the literature lacks satisfactory general information about the pathology. The aim of this study was to review our experiences in the diagnosis and treatment of visceral artery aneurysms.

MATERIALS AND METHODS

We retrospectively reviewed data on 10 patients who were diagnosed with visceral artery aneurysms at our institution between June 2002 and September 2005. All available clinical, pathologic, and postoperative data were reviewed and analyzed for postoperative outcome.

RESULTS

Four splenic artery aneurysms, 2 hepatic artery aneurysms, 5 renal artery aneurysms, 1 superior mesenteric artery aneurysm, and 1 inferior mesenteric artery aneurysm (13 total visceral artery aneurysms) were diagnosed in 10 patients. All the patients were treated except 1 patient with bilateral renal artery aneurysms. One patient required emergent surgical treatment due to splenic artery aneurysm rupture. Only 1 patient underwent endovascular treatment (ie, coil embolization for a superior mesenteric artery aneurysm); otherwise all the patients were treated surgically on an elective basis. Surgical treatment modalities included ligation with exclusion in 4 patients (2 splenic artery aneurysms, 1 renal artery aneurysm, 1 hepatic artery aneurysm) and resection with revascularization in 4 patients (1 splenic artery aneurysm, 2 renal artery aneurysms, 1 hepatic artery aneurysm, 1 inferior mesenteric artery aneurysm). Histopathologic examination of the vascular materials revealed major atherosclerotic changes except one that showed inflammatory vasculitic changes. One patient required bleeding revision, and mortality did not occur in any of the patients.

CONCLUSIONS

Visceral artery aneurysms are rare and potentially life-threatening vascular disorders. The number of cases diagnosed every year increases because of advanced radiologic diagnostic methods and screening programs. Careful consideration and early management of these malformations can be life saving.

Identification of risk factors for perioperative mortality in acute mesenteric ischemia

INTRODUCTION

Acute intestinal ischemia is in most cases a lethal condition with a low survival rate. Risk factors of perioperative mortality are poorly defined. The aim of this study was to define risk factors that predict an adverse outcome of acute mesenteric ischemia (AMI).

METHODS

A total of 132 consecutive patients (73 men, 59 women), mean+/-SD age 71.96+/-13.64 years, who underwent surgery because of AMI in a university tertiary care center were evaluated over a period of 10 years. Clinical features, laboratory findings, etiologic factors, and surgical procedures were recorded and assessed as possible risk factors for perioperative mortality.

RESULTS

Of 132 patients, 86 (65.2%) died during the perioperative period as a direct result of AMI. Significant univariate predictors of perioperative mortality were age (P=0.01), cardiopathy (P=0.002), digoxin intake (P=0.015), shock (P=0.01), urea plasma level (P<0.001), creatinine (P<0.001), potassium (P=0.042), low pH (P=0.015) and bicarbonate (P=0.035); hemoglobin>or=2.48 mmol/L (P=0.035); time delay to surgery (P=0.023); colonic involvement (P<0.001); small and large bowel involvement (P<0.001); arterial versus venous ischemia (P=0.007); and intestinal resection (P<0.001). In the multivariate analysis, the variables previous cardiac illness (P=0.045), urea plasma levels (P<0.001), and small and large bowel involvement were identified as independent risk factors of perioperative mortality. Intestinal resection (P<0.001) was a favorable predictor.

CONCLUSIONS

Age, time delay to surgery, shock, and acidosis significantly increase the risk of mortality due to AMI, whereas intestinal resection has a protective effect. However, only previous cardiac illness, acute renal failure, and large bowel ischemia have a negative effect as independent risk factors of mortality of AMI.

Spatial separation of endothelial small- and intermediate-conductance calcium-activated potassium channels (K(Ca)) and connexins: possible relationship to vasodilator function?

Activation of endothelial cell small- (S) and intermediate- (I) conductance calcium-activated potassium channels (K(Ca)) and current or molecular transfer via myoendothelial gap junctions underlies endothelium-derived hyperpolarization leading to vasodilation. The mechanism underlying the K(Ca) component of vasodilator activity and the characteristics of gap junctions are targets for the selective control of vascular function. In the rat mesenteric artery, where myoendothelial gap junctions and connexin (Cx) 40 are critical for the transmission of the endothelial cell hyperpolarization to the smooth muscle, SK(Ca) and IK(Ca) provide different facets of the endothelium-derived hyperpolarization response, being critical for the hyperpolarization and repolarization phases, respectively. The present study addressed the question of whether this functional separation of responses may be related to the spatial localization of the associated channels? The distribution of endothelial SK(Ca) and IK(Ca) and Cx subtype(s) were examined in the rat mesenteric artery using conventional confocal and high-resolution ultrastructural immunohistochemistry. At the internal elastic lamina-smooth muscle cell interface at internal elastic lamina holes (as potential myoendothelial gap junction sites), strong punctate IK(Ca), Cx37 and Cx40 expression was present. SK(Ca), Cx37, Cx40 and Cx43 were localized to adjacent endothelial cell gap junctions. High-resolution immunohistochemistry demonstrated IK(Ca) and Cx37-conjugated gold to myoendothelial gap junction-associated endothelial cell projections. Clear co-localization of K(Ca) and Cxs suggests a causal relationship between their activity and the previously described differential functional activation of SK(Ca) and IK(Ca). Such precise localizations may represent a selective target for control of vasodilator function and vascular tone.

[Splanchnic artery aneurysms]

INTRODUCTION

Splanchnic artery aneurysms are uncommon but important vascular entity because nearly 25% of all cases present as surgical emergency.

OBJECTIVE

The purpose of our study was to present nine patients operated on at the Institute of cardiovascular diseases, as well as literature review of clinical presentation of the disease.

METHOD

There were three splenic artery aneurysms, two celiac trunk aneurysms, and one aneurysm of the hepatic, superior mesenteric, inferior mesenteric and gastroduodenal artery. All patients were males, mean aged 67.5 years (60-73). In four patients, splanchnic artery aneurysm was discovered accidentally during routine ultrasonographic and angiographic examinations of the abdominal aorta. At that time, arteriovenous fistula was diagnosed in a patient No 1; it was formed after rupture of the splenic artery aneurysm into the splenic vein. Three aneurysms were manifested by abdominal pain and palpable pulsating abdominal mass. Two patients were admitted as urgent cases in the state of hemorrhagic shock and signs of intraabdominal bleeding due to rupture of the splenic and hepatic arteries. In 7 cases, diagnosis was made preoperatively by means of ultrasonography and angiography; in two patients, accurate diagnosis was confirmed during surgery.

RESULTS

Proximal and distal ligation of the artery was performed in a patient with rupture of the splenic aneurysm into the splenic vein that caused arteriovenous fistula. Gastroduodenal artery aneurysm was treated by trans-aneurysmatic ligation of its "entering" and "exiting" branches. Aneurysms of distal part of the superior mesenteric and splenic artery were resected without further reconstruction. Partial resection of the aneurysm and endoaneurysmorrhaphy was carried out in one case of celiac trunk aneurysm, and in another, after aneurysm resection, the restoration of blood flow through the hepatic and lienal artery was achieved by Dacron grafts. In a patient with the inferior mesenteric artery aneurysm, the resection of aneurysm was followed by reimplantation of medial part of the artery into bifurcated Dacron graft which replaced abdominal aorta. In 5 patients, some of additional surgical procedures were performed. There were 4 reconstructive procedures of abdominal aorta and one splenectomy. The patient with ruptured hepatic artery aneurysm died during surgery due to uncontrolled hemorrhage. In other patients, there was neither morbidity nor mortality in the early postoperative period (first 30 days after surgery). Mean follow up was 1 to 5 years (mean 3.4 years). One patient died after 5 years due to myocardial infarction.

CONCLUSION

Although the introduction of precise diagnostic procedures (computerized tomography, magnetic resonance imaging, spiral scan) make diagnosis easier, the splanchnic artery aneurysms are still difficult to detect due to their uncommon clinical presentations.

Chronic mesenteric ischemia: stenting of mesenteric arteries

This article focuses on stent placement in mesenteric arteries in patients with the rare diagnosis of chronic mesenteric ischemia. We present a survey from the initial stage of recognition of this gastrointestinal disorder and its manifestations to treatment by stenting to avoid further ischemic episodes and bowel infarction and necrosis. The advantages of stent placement in splanchnic arteries are discussed in comparison to open surgical revascularization.

Assessment of patients with acute mesenteric ischemia: multislice computed tomography signs and clinical performance in a group of patients with surgical correlation

AIM

The aim of this paper was to describe signs and performance of multislice computed tomography (MSCT) in patients with acute mesenteric infarction (AMI).

METHODS

MSCT examinations of 26 patients with AMI and of 34 patients with acute abdomen and surgical diagnosis excluding AMI were retrospectively analyzed. All studies were performed with arterial and portal venous phase scans, 2.5 mm thickness, 1.25 mm image interval. All abnormal findings at MSCT in patients with AMI were recor- ded. Patients with MSCT evidence of mesenteric artery occlusion or pneumatosis or venous gas or, alternatively, bowel thicken-ing associated with lack of wall enhancement or venous thrombosis or parenchimal infarction were considered to be affected by AMI.

RESULTS

AMI was due to mesenteric artery thrombosis in 17 patients, mesenteric vein thrombosis in 7, and nonocclusive ischemia in 2. In 16/17 patients arterial thrombosis was visualized, in 7/7 venous thrombosis was found. Portal or mesenteric vein gas was seen in 5% and pneumatosis in 38%; bowel wall thickening associated with other signs was found in 31%. Sensitivity and specificity were 92% and 100%, respectively.

CONCLUSIONS

MSCT allows an accurate assessment of the mesenteric circulation and the bowel wall. This makes possible optimal visualization of signs of AMI resulting in a good clinical performance.

[Acute mesenteric ischemia in a patient with relapsing polychondritis]

We report about a 43-year old woman with relapsing polychondritis, admitted with progressive malaise, fatigue, anorexia and profound weight loss. Two years ago a nasal chondritis with characteristic changes of the nasal profil, scleritis, laryngitis and unspecific general symptoms (fever, fatigue, signs of a systemic inflammation) developed and relapsing polychondritis was diagnosed. The patient was treated initially with azathioprine followed by methotrexate in combination with ciclosporine and glucocorticoids. During the hospitalization her condition slowly worsened, and crampy abdominal pain developed subsequently with massive tenderness, rebound and guarding. The clinically presumed diagnosis of ileus and peritonitis was radiomorphologically confirmed with signs of enteric perforation and a laparatomy was performed. A complete occlusion of the A. mesenterica superior and stenosis of the truncus coeliacus were diagnosed followed by a revascularization with an aorto-mesenteric bypass and subsequent resection of the necrotic ischemic ileum. An association with various autoimmune disorders including vasculitic syndromes is well known for relapsing polychondritis. The case demonstrated a progressive mesenteric ischemia with the acute exacerbation caused by a vasculitic mesenterial occlusion. The unusual presentation should be considered in the differential diagnosis of uncommon abdominal symptoms during the course of relapsing polychondritis.

Endothelin is a dose-dependent trophic factor and a mitogen in small arteries in vivo

OBJECTIVE

Endothelin (ET) modulates cellular processes relevant to vascular remodeling, but there is still some debate as to the potential of ET to be a trophic factor or a mitogen. Moreover, the signaling of ET in vivo to produce these effects is largely unknown.

METHODS

3H-leucine and 3H-thymidine incorporation in rat small mesenteric arteries was studied with several doses of ET-1 (0.1-10 pmol/kg/min) administered for 26 h in vivo.

RESULTS

The EC50 for protein synthesis was four times lower than that of DNA synthesis, with maximal effects around 1 and 3 pmol/kg/min, respectively. At 5 pmol/kg/min, ET enhanced CDK2 activity by reducing the binding of its inhibitor p27(Kip1). In contrast, the binding was enhanced at 0.5 pmol/kg/min. The reduced binding observed at 5 pmol/kg/min could not be explained by changes of p27(Kip1) or CDK2 content. Phosphorylation of p27(Kip1) on serine 10 was significantly reduced at 5 pmol/kg/min ET. Although the phosphoinositide 3-kinase pathway was activated, it did not contribute to the protein or DNA synthesis responses. Administration of 1 or 5 pmol/kg/min ET-1 for 28 days increased the thickness and cross-sectional area of the small mesenteric artery due to hypertrophy and hyperplasia, respectively, thus confirming the results obtained in acute conditions.

CONCLUSION

ET modulates p27(Kip1) binding to CDK2, producing hypertrophy at low and hyperplasia at higher concentrations. Taken together, these results suggest that ET can act both as a trophic factor and as a mitogen in an in vivo environment, depending on its local concentration.

Endothelin-1-induced oxidative stress in DOCA-salt hypertension involves NADPH-oxidase-independent mechanisms

We have demonstrated recently [Callera, Touyz, Teixeira, Muscara, Carvalho, Fortes, Schiffrin and Tostes (2003) Hypertension 42, 811-817] that increased vascular oxidative stress in DOCA (deoxycorticosterone acetate)-salt rats is associated with activation of the ET (endothelin) system via ETA receptors. The exact source of ET-1-mediated oxidative stress remains unclear. The aim of the present study was to investigate whether ET-1 increases generation of ROS (reactive oxygen species) in DOCA-salt hypertension through NADPH-oxidase-dependent mechanisms. Xanthine oxidase, eNOS (endothelial nitric oxide synthase) and COX-2 (cyclo-oxygenase-2) were also examined as potential ET-1 sources of ROS as well as mitochondrial respiration. DOCA-salt and control UniNX (uninephrectomized) rats were treated with the ETA antagonist BMS182874 (40 mg.day(-1).kg(-1) of body weight) or vehicle. Plasma TBARS (thiobarbituric acid-reacting substances) were increased in DOCA-salt compared with UniNX rats. Activity of NADPH and xanthine oxidases in aorta, mesenteric arteries and heart was increased in DOCA-salt rats. BMS182874 decreased plasma TBARS levels without influencing NADPH and xanthine oxidase activities in DOCA-salt rats. Increased p22(phox) protein expression and increased p47(phox) membrane translocation in arteries from DOCA-salt by rats were not affected by BMS182874 treatment. Increased eNOS and COX-2 expression, also observed in aortas from DOCA-salt rats, was unaltered by BMS182874. Increased mitochondrial generation of ROS in DOCA-salt rats was normalized by BMS182874. ETA antagonism also increased the expression of mitochondrial MnSOD (manganese superoxide dismutase) in DOCA-salt rats. In conclusion, activation of NADPH oxidase does not seem to be the major source of oxidative stress induced by ET-1/ETA in DOCA-salt hypertension, which also appears to be independent of increased activation of xanthine oxidase or eNOS/COX-2 overexpression. Mitochondria may play a role in ET-1-driven oxidative stress, as evidenced by increased mitochondrial-derived ROS in this model of hypertension.

Obstruction of the ileal ureter by mesenteric vessels occurring 5 years after total ureteral substitution for bilateral ureteral stenosis due to systemic lupus erythematosus

We previously reported a case of bilateral ureteral stenosis accompanied by systemic lupus erythematosus, which was successfully managed by total ureteral reconstruction using a segment of the ileum. Herein, we describe an unusual complication in the same patient, which we experienced 5 years after the ileal-ureteral substitution. Left-sided back pain repeated together with transient obstruction of the ileal ureter interposed between the right and left renal pelvis. Consequently, exploratory laparotomy revealed that left colic vessels oppressed and caused obstruction, and the obstructed ileal ureter was released by reconstitution of these vessels instead of re-anastomosis of the ileal ureter. Left hydronephrosis and related back pain disappeared postoperatively. The number of patients with an indication of ileal-ureteral substitution is increasing for various disorders, and thus, the present report gives additional suggestions for the follow up of patients with ileal ureter.

Effect of Ruminally Protected Methionine on Splanchnic Metabolism of Amino Acids in Lactating Dairy Cows

The effect of ruminally protected Met (RPM) on splanchnic metabolism was measured in 3 primiparous and 3 multiparous Holstein cows. Doses of RPM (0, 36, and 72 g/d) were tested in a replicated 3 x 3 Latin square design, over 3 consecutive 14-d experimental periods. A mixed ration was fed in 12 equal meals per d (average dry matter intake: 17.5 +/- 0.08 kg/d). Indwelling catheters were surgically implanted in the mesenteric artery and the portal and hepatic veins for blood collection, as well as in 2 distal branches of the mesenteric vein for infusion of p-aminohippurate to determine blood flow. On d 14 of each period, a temporary catheter was inserted into a mammary vein and 6 hourly blood samples were collected to determine plasma concentrations of metabolites, hormones, and their respective fluxes across the splanchnic bed and mammary glands. Yields of milk (32.8, 32.0, and 32.9 +/- 0.92 kg/d) and protein (1,028, 1,053, and 1,075 +/- 28.7 g/d) were unaffected by level of RPM. However, the true protein content in milk from primiparous cows increased linearly (2.92, 3.09, and 3.34 +/- 0.077%). The addition of RPM linearly increased the net flux of Met across the portal-drained viscera, which resulted in increased arterial Met concentrations (25, 29, and 40 +/- 1.1 microM). Although it had no significant effect on net portal and hepatic fluxes of other essential amino acids, RPM resulted in a linear increase in the total splanchnic output of Ile, Leu, Phe, and Thr. These results suggest that feeding RPM triggered a homeostatic response resulting in less utilization of certain essential amino acids through the gastrointestinal tract and liver. Net mammary uptake of Met did not change with the addition of RPM. However, mammary extraction of Met decreased in a linear fashion in response to increased arterial inflow.

Mesenteric pseudoaneurysm in a 12-year-old girl with abdominal tuberculosis presenting with massive lower gastrointestinal bleeding

We report a case of a 12-year-old girl with a mesenteric pseudoaneurysm and abdominal tuberculosis presenting with massive lower gastrointestinal hemorrhage requiring multiple blood transfusions. The pseudoaneurysm was treated successfully with transarterial microcoil embolization. Pseudoaneurysms are a rare and life-threatening complication of tuberculosis and understanding the imaging characteristics and treatment options will help to guide appropriate therapy.

[Visceral artery aneurysms]

INTRODUCTION

The aim of this study was to review our experience in the diagnosis and treatment of visceral artery aneurysms.

MATERIAL AND METHOD

We performed a retrospective study through review of the medical records of patients diagnosed with visceral aneurysms from 1984 to 2003. Diagnosis, treatment and follow-up were analyzed.

RESULTS

Thirty-two aneurysms were diagnosed in 27 patients (17 men and 10 women). There were 12 aneurysms of the splanchnic artery, six of the hepatic artery, five of the celiac trunk, three gastroduodenal, one jejunal, one pancreaticoduodenal, one superior mesenteric--associated with a splanchnic, renal and celiac trunk aneurysm--, one inferior mesenteric, one cystic artery and one case of parenchymatous hepatorenal microaneurysms. Eight aneurysms were not treated. Three underwent embolization. One aneurysm was excluded with a covered endoprosthesis. Twenty aneurysms were treated surgically. Ligature or exclusion was performed in 11 patients, hepatic lobectomy in one patient, resection with revascularization in four patients, endoaneurysmorrhaphy in three patients and simple suture was performed in one hepatic artery pseudoaneurysm.

CONCLUSIONS

Current diagnostic techniques favor early and sometimes minimally invasive treatment. Splanchnic aneurysms are more difficult to diagnose and require highly varied repair techniques.

Stent Placement with the Monorail Technique for Treatment of Mesenteric Artery Stenosis

PURPOSE

To analyze the immediate and midterm success of stenting of mesenteric arteries by a monorail technique in patients with chronic mesenteric ischemia.

MATERIALS AND METHODS

In this prospective case series, 19 patients (11 male, 8 female; mean age, 62.9 +/- 10.4 y; range, 36-82 y) with 23 symptomatic stenoses of mesenteric arteries were treated with stent placement by a monorail technique in a radiologic intervention center over a period of 4.5 years. Clinical examinations and duplex sonography were used to evaluate the stents' patency and clinical success. Kaplan-Meier graphs were calculated to analyze the patency and freedom-from-symptom rate.

RESULTS

Initial technical success rate was 22/23 (96%). Mean follow-up was 17 months (range, 1-58 mo). Primary patency and primary clinical success rates were 82% and 78%, respectively. According to Kaplan-Meier tables, the patency rates were 96%, 87%, 76%, and 61% at 0, 1, 15, and 24 months, respectively, and the freedom-from-symptom rates were 95%, 90%, 72%, and 54% at 0, 1, 24, and 30 months, respectively. No peri-interventional complications occurred. Two patients died of cardiac failure in the hospital within 30 days after intervention; deaths were not related to the intervention.

CONCLUSIONS

Stent placement by a monorail technique in mesenteric arteries is an effective and safe treatment for symptomatic stenoses in patients with chronic mesenteric ischemia after a mean follow-up of 17 months.

Kinetics of the appearance of cereal alkylresorcinols in pig plasma

Alkylresorcinols (AR) are phenolic lipids found in high amounts in wholegrain wheat and rye. They may be important as bioactive components and/or biomarkers of wholegrain wheat and rye intake. AR absorption was studied with pigs during a habitual diet and after a single meal of AR-rich diet. In study 1, four pigs were fed wholegrain rye (RD) and white wheat bread (WD) for 1 week in a cross-over design. Arterial and venous AR concentrations were determined over 540 min after feeding on days 5 and 7. In study 2, four pigs were fed a synthetic, starch-based diet for 5 d, and arterial and venous AR concentrations were determined over 960 min after feeding a single meal of RD. In study 1, plasma AR concentrations after consuming RD peaked at 120 min, remained elevated between 120 and 420 min, and were re-elevated on refeeding at 480 min. In study 2, AR appeared in the plasma after 60 min, peaked at 180-240 min, and remained elevated after 960 min. The apparent elimination half-life was 3.93 h, and the maximum plasma concentration was 666 (sem 35) nmol/l. Arterial and venous plasma AR concentrations were similar, suggesting that AR are absorbed via the lymphatic system. AR concentrations in pig plasma increase rapidly after a meal containing AR, and persist in plasma for at least 5 d, indicating that AR may be a useful biomarker of wholegrain wheat and rye intake.