Studies on Cycloalkane-Based Bisamide Organogelators: A New Example of Stochastic Chiral Symmetry-Breaking Induced by Sonication

Enantiomerically pure C₁₆ -alkyl amides derived from cis and trans cycloalkane-1,2-dicarboxylic acids, respectively, have been synthesized and their behavior as organogelators has been investigated. These compounds include cis/trans diastereomeric cyclobutane and cyclohexane derivatives with the aim to explore the influence of the ring size as well as the relative configuration in their hierarchical self-assembly to form gels. High resolution ¹ H NMR spectroscopy studies allowed the determination of the dynamics of the gelation process in [D₈ ]toluene and the sol-gel transition temperature. The morphology and size of the aggregates have been investigated and results have shown that, in the case of cyclobutane derivatives, the cis/trans stereochemistry is not relevant for the gelation behavior and the properties of the soft-materials obtained, but it is remarkable for cyclohexane diamides, which are better organogelators. The four compounds produce chiral aggregates despite that two of them are meso achiral molecules. We show herein that this fact is an example of stochastic symmetry breaking induced by sonication. The self-assembly of these molecules has been modelled providing information and support about the structure and the chirality of the aggregates.

A new β⁰-thalassemia frameshift mutation [β 48 (-T)] in a Uruguayan family

We describe here a new frameshift mutation of β-thalassemia in a Uruguayan family with Italian ancestry [β48 (-T); HBB:c.146delT]. This frameshift results in formation of premature stop codon (TGA) 40 bp downstream and in a short unstable product that is degraded in the cell.

Stereoselective synthesis of all stereoisomers of orthogonally protected cyclobutane-1,2-diamine and some chemoselective transformations

The four stereoisomers of protected cyclobutane-1,2-diamine have been prepared in an enantio- and diastereocontrolled manner through stereodivergent synthetic routes starting from a half-ester as a common chiral precursor. Orthogonal protection allows the chemoselective manipulation of both amino groups as shown in this work.

Mitochondrial DNA in Basque descendants from the city of Trinidad, Uruguay: Uruguayan- or Basque-like population?

Like other countries in the Americas, during its colonization Uruguay was the recipient of immigrants from several ethnic groups from Europe, as well as of enslaved Africans. After its independence in 1830, Basques were the first group of Europeans to arrive in the country. In this paper, we aim to contribute to the understanding of the process of integration of these migratory waves into the Uruguayan society. For that purpose, individuals of Basque origin from the city of Trinidad, Uruguay, were chosen to participate in this study. Particularly, we wanted to determine if Basque descendants in Uruguay remained relatively isolated or if they mixed with other ethnic groups. Mitochondrial DNA (mtDNA) of 60 self-identified Basque descendants, taken from a larger sample of subjects with Basque ancestors, was analyzed. The origin of mtDNA haplogroups was 77.8% European, 20.4% Amerindian, and 1.8% African, showing similar frequencies to other Uruguayan regions. Very few sequences showed a clear Basque origin, although other sources such as the Canary Islands are likely. Moreover, genetic distances clearly show that Basque descendants are genetically closer to other Uruguayan groups than to European populations, including Basques. It is possible to conclude that Basques and their descendants in the region of Trinidad did not remain isolated and that their marriage behavior was similar to that of other Uruguayan populations. However, to have a more accurate picture of the way Basques intermarried with other populations in Uruguay, new analyses are needed that take into account paternal lineages as well as biparental genetic markers.

[Impact of (18)F-FDG PET/CT on the therapeutic management in the initial staging of the esophageal cancer]

OBJECTIVE

The incidence of esophageal cancer has increased considerably over recent years, it now being the 6th most frequent cause of cancer-related death. Our study has aimed to compare the clinical value of PET/CT and CT scan in the initial staging of patients with esophageal cancer.

MATERIAL AND METHODS

Fifty nine patients (6 women) diagnosed of esophageal cancer were assessed retrospectively. All patients underwent diagnostic CT scan and PET/CT for initial staging within 3 to 15 days following clinical diagnosis.

RESULTS

PET/CT showed intracellular (18)F-FDG entrapment having pathological significance in all the tumors (100%), signs of locoregional lymph node infiltration (N1) in 34 and a total of 19 lesions consistent with metastasis (M1) in 14 patients (23.72%). The CT scan detected malignancy in 57 patients (96.6%), abnormal lymph node in 32 patients and 17 N1 in 12 patients (20.33%). In three cases, CT- PET detected synchronous esophageal lesion in staging studies for other neoplastic processes (lung and ear-nose-throat).

CONCLUSION

PET/CT showed a higher detection rate of primary malignant lesions, abnormal lymph nodes and distant metastases. A change in stage was only observed in two patients.

Time course of necrosis/apoptosis and neovascularization during experimental gastric conditioning

Apoptosis, necrosis and neovascularization are three processes that occur during ischemic preconditioning in a range of organs. In the stomach, the effect of this preconditioning (the delay phenomenon) has helped to improve gastric vascularization prior to esophagogastric anastomosis after esophagectomy. Here we present a sequential study of the histological recovery of the gastric fundus and the phenomena of apoptosis, necrosis and neovascularization in an experimental model of partial gastric ischemia. Partial gastric devascularization was performed by ligature of the left gastric vessels in Sprague-Dawley rats. Rats were assigned to groups in accordance with their evaluation period: control, 1, 3, 6, 10, 15 and 21 days. Histological analysis, caspase-3 activity, DNA fragmentation and vascular endothelial cell proliferation (Ki-67) were measured in tissue samples after sacrifice. After 24 h of partial gastric ischemia, rates of apoptosis and necrosis were higher in the experimental groups than in controls. Tissue injury was higher 3 and 6 days post-ischemia. From day 10 after partial gastric ischemia, apoptosis and necrosis started to decrease, and on days 15 and 21 showed no differences in relation to controls. Neovascularization began between days 1 and 3, reaching its peak at 15 days after ischemia and coinciding with complete histological recovery. Both necrosis and apoptosis play a role in tissue injury during the first days after partial gastric ischemia. After 15 days, the evolution of both the histology and the neovascularization suggested that this is the optimal time for performing gastric transposition.

Efficacy of enteral decontamination in the prevention of anastomotic dehiscence and pulmonary infection in esophagogastric surgery

Our aim in this study is to evaluate the efficacy of decontamination of the high digestive tract in reducing the incidence of anastomotic dehiscence, pulmonary infection and mortality after resective gastro-esophageal surgery. A prospective randomized and double-blinded study was conducted in patients undergoing total gastrectomy for gastric cancer and esophagectomy for esophageal cancer. Two groups were studied: group A patients were given erythromycin + gentamicine + nistatine sulfate orally; group B patients were given placebo. Mortality, incidence of anastomotic dehiscence and incidence of pulmonary infection were the end points evaluated. One hundred and nine consecutive patients were randomized. Eighteen (16.5%) were excluded. From the 91 patients who were evaluated, 42 (46.2%) received an esophagectomy and 49 (53.8%) had a total gastrectomy. Esophagectomies showed: a 0% rate of anastomotic dehiscence in group A and 12.5% in group B, P = 0.176; a pulmonary infection rate of 22.2% in group A and 29.1% in group B, P = 0.443; and mortality rate was 0% in group A and 12.5% in group B, P = 0.176. After gastrectomy, anastomotic dehiscence rate was 4.5% in group A and 0% in group B, P = 0.449; pulmonary infection rate was 4.5% in group A and 11.1% in group B, P = 0.387 and mortality was 9% in group A and 0% in group B, P = 0.196. Decontamination protocol does not help in decreasing the incidence of anastomotic dehiscence, pulmonary infection and mortality in the present study. Nevertheless, there seems to be a tendency to low pulmonary infection after gastrectomy and esophagectomy and to improve the incidence of anastomotic dehiscence after esophagectomy. Further studies are needed to re-evaluate these findings.

Combined type-1 plasminogen activator inhibitor and NOD2/CARD15 genotyping predicts complicated Crohn's disease behaviour

BACKGROUND

NOD2/CARD15 gene variants have not been universally associated with stricturing behaviour in Crohn's disease. Other behaviour modifying genes could explain these results.

AIM

To study the combined influence of NOD2/CARD15 variants and 4G/4G genotype of type-1 plasminogen activator inhibitor (PAI-1) gene on Crohn's disease behaviour.

METHODS

One hundred and seventy Crohn's disease patients were studied prospectively, with a mean follow-up of 7+/- 6 years. Disease behaviour was registered by using two criteria: the Vienna classification and a non-hierarchical classification based on the behavioural Vienna categories.

RESULTS

In the multivariate analysis for stricturing behaviour according to the Vienna categories, only absence of colonic disease (OR, 4.0; 95% CI: 1.49-11.1; P = 0.006) was an independent predictive factor. However, in the multivariate analysis for stricturing disease applying a non-hierarchical criteria, ileal disease (OR, 4.19; 95% CI: 1.30-13.5; P = 0.01), and carrying both NOD2/CARD15 variants and the 4G/4G PAI-1 genotype (OR, 5.02; 95% CI: 1.44-17.48; P = 0.01) were independent predictive factors. In the multivariate analysis for penetrating behaviour, the 4G/4G PAI-1 (OR, 3.10; 95% CI: 1.54-6.23; P = 0.001) and male sex (OR, 2.44; 95% CI: 1.30-4.60; P = 0.005) were independent predictive factors irrespective of criteria applied.

CONCLUSIONS

Combined PAI-1 and NOD2/CARD15 genotyping predict complicated Crohn's disease. Patients with these variants could benefit from early interventions.

Anti-inflammatory effects of pancreatitis associated protein in inflammatory bowel disease

BACKGROUND AND AIMS

Increased pancreatitis associated protein (PAP) mRNA has been reported in active inflammatory bowel disease (IBD). The aims of the current study were to characterise PAP production in IBD and the effects of PAP on inflammation.

PATIENTS AND METHODS

Serum PAP levels were determined in healthy controls (n = 29), inflammatory controls (n = 14), and IBD patients (n = 171). Ex vivo PAP secretion in intestinal tissue was measured in 56 IBD patients and 13 healthy controls. Cellular origin of PAP was determined by immunohistochemistry. The effects of exogenous PAP on nuclear factor kappaB (NFkappaB) activation, proinflammatory cytokine production, and endothelial adhesion molecule expression were also analysed ex vivo.

RESULTS

Patients with active IBD had increased serum PAP levels compared with controls, and these levels correlated with clinical and endoscopic disease severity. Ex vivo intestinal PAP synthesis was increased in active IBD and correlated with endoscopic and histological severity of inflammatory lesions. PAP localised to colonic Paneth cells. Incubation of mucosa from active Crohn's disease with PAP dose dependently reduced proinflammatory cytokines secretion. PAP prevented TNF-alpha induced NFkappaB activation in monocytic, epithelial, and endothelial cells and reduced proinflammatory cytokine mRNA levels and adhesion molecule expression.

CONCLUSIONS

PAP is synthesised by Paneth cells and is overexpressed in colonic tissue of active IBD. PAP inhibits NFkappaB activation and downregulates cytokine production and adhesion molecule expression in inflamed tissue. It may represent an anti-inflammatory mechanism and new therapeutic strategy in IBD.

First measurement of the transverse spin asymmetries of the deuteron in semi-inclusive deep inelastic scattering

First measurements of the Collins and Sivers asymmetries of charged hadrons produced in deep-inelastic scattering of muons on a transversely polarized 6LiD target are presented. The data were taken in 2002 with the COMPASS spectrometer using the muon beam of the CERN SPS at 160 GeV/c. The Collins asymmetry turns out to be compatible with zero, as does the measured Sivers asymmetry within the present statistical errors.

Consanguinity in two Uruguayan cities: historical evolution and characteristics (1800-1994)

BACKGROUND

Information about consanguinity in Uruguay is scarce and limited to the end of the 20th century.

AIM

To determine the frequency and characteristics of consanguineous marriages, as well as chronological trends, in two Uruguayan cities over almost two centuries.

SUBJECTS AND METHODS

We analysed 28,393 Roman Catholic Church marriage records and Diocesan consanguinity dispensations belonging to the cities of Melo (Northeast), and Montevideo (South), for the period 1800--1994.

RESULTS

633 (2.23%) marriages were consanguineous. Among them, first cousin marriages were the most common (58.8% of all consanguineous marriages, including double consanguineous), especially those where the bride and groom were related through their maternal side. During the first decades of the 19th century both regions showed low levels of consanguinity. Consanguinity reached its maximum during the mid-1800s and decreased significantly throughout the 20th century. The overall mean coefficients of inbreeding were moderate in both cases, being greater in the Northeast (alpha=0.00165) than in the South (alpha = 0.00089).

CONCLUSIONS

The low level of consanguinity as well as the structure of consanguineous marriages (distribution by degrees) is similar to that found in other southern South American countries. Temporal trends are similar to those found in industrialized regions in Europe, with maximum inbreeding levels during the middle-late 19th century; however, the clear predominance of first cousin unions, differs from most of the data for European countries. Small differences between the two cities can be related to diverse facts, such as socio-economic conditions, ethnic origin, immigration, and sampling.

Platelets: new players in the mucosal scenario of inflammatory bowel disease

Besides their classical haemostatic task, platelets are now recognized as novel cells deeply involved in inflammation. Compelling evidence support their role as active player in mucosal tissue injury that occurs in Crohn's disease and ulcerative colitis. In both forms of inflammatory bowel disease platelets contribute to microvascular endothelial activation and recruitment of inflammatory cells, thus fostering and amplifying mucosal inflammation.

The 4G/4G genotype of the 4G/5G polymorphism of the type-1 plasminogen activator inhibitor (PAI-1) gene is a determinant of penetrating behaviour in patients with Crohn's disease

BACKGROUND

Crohn's disease is a heterogeneous disorder with polygenic inheritance.

AIM

To assess the effect of the 4G/5G polymorphism of the type-1 plasminogen activator inhibitor (PAI-1) gene, the major inhibitor of fibrinolysis, on Crohn's disease susceptibility and phenotype.

METHODS

One hundred and fifty-seven patients with Crohn's disease and 350 controls were included prospectively. Medical records were reviewed to determine changes in the Crohn's disease phenotype. The 4G/5G polymorphism was assessed by polymerase chain reaction techniques.

RESULTS

The frequencies of the 4G/4G, 4G/5G and 5G/5G genotypes were similar in patients with Crohn's disease and controls. The 4G/4G genotype (P < 0.0001; odds ratio, 4.84) and male sex (P = 0.009; odds ratio, 2.63) were independent risk factors for penetrating behaviour in Crohn's disease. Most Crohn's disease patients had a non-penetrating phenotype at diagnosis. The probability of development of a penetrating phenotype within 5 years of diagnosis was higher in patients with the 4G/4G genotype (72% vs. 19%, P < 0.0001).

CONCLUSIONS

The 4G/4G genotype of the PAI-1 gene does not influence Crohn's disease susceptibility, but increases by five-fold the probability of penetrating behaviour. Most patients with the 4G/4G genotype have a non-penetrating phenotype at diagnosis, but develop a penetrating behaviour within 5 years. Genotyping the 4G/5G polymorphism may be useful for the identification of a sub-group of patients with aggressive Crohn's disease, who might benefit from specific therapy.

[Frequent Internet use among Catalan patients with inflammatory bowel disease]

No data are available on the use of the Internet by Spanish patients with chronic diseases.

AIM

To determine the extent to which patients with inflammatory bowel disease (IBD) in Barcelona (Spain) make use of the Internet and the relationship between Internet use and demographic characteristics.

METHOD

A questionnaire on Internet use was administered to 200 patients attending an information session on IBD organized by the Gastroenterology Department of a university referral hospital in the city of Barcelona.

RESULTS

Replies were received from 86% of those surveyed. The mean age was 40 years and 60% were women. Sixty-eight percent had home computers and 49% had an Internet connection. Forty-four percent sporadically or regularly obtained information on IBD from the web. A positive correlation was found between availability and Internet use and young age and higher educational level. No differences were found between men and women. Eighty-four percent expressed interest in having a web site on IBD supported by the physicians of their referral center and 65% were prepared to pay a subscription for this service.

CONCLUSION

Patients with IBD from Barcelona frequently looked for information on their disease on the Internet and were receptive to initiatives concerning electronic information from physicians of their local referral center.

[Carriers of hepatitis C: should they all be vaccinated for hepatitis A?]

AIM

To investigate the prevalence of immunization against hepatitis A virus (HAV) in persons with hepatitis C virus (HCV) infection, in order to determine who should be vaccinated for the former.

DESIGN

Descriptive, cross-sectional study.

SETTING

Urban health center serving 12 000 inhabitants.

PARTICIPANTS

Patients older than 14 years positive for HCV infection.

MAIN MEASURES

VARIABLES

presence of chronic liver disease, serological indications of hepatitis B, A, and immune deficiency virus (HIV) infection, vaccination for hepatitis B.

RESULTS

A total of 134 persons (70.9% men and 29.1% women) comprised the sample of patients positive for HCV infection. Mean age was 41.75 years (SD, 16.55 years). Nearly all patients (93.3%) had chronic liver disease, 56.7% were intravenous drug users, 56% were positive for Hbc antibodies and 32.8% were positive for HIV. Serological testing for HAV was done in 75 patients (56%); the result was positive in 86.7%. Mean age in this subgroup was 50.4 years (SD, 17.8 years). In the HAV-negative subgroup, mean age was 36.6 years (SD, 15 years; P=.02). Serological testing for HAV could not be done in 44% of the patients: 33.6% did not respond to attempts to contact them by telephone or in writing, 6% were temporarily away from home, and 1 patient declined to be tested. The response to requests to obtain blood samples was better in women (66.7%), HIV-negative patients (34.7%), persons who were not intravenous drug users (43.3%) and persons with chronic liver disease (60%).

CONCLUSIONS

In persons younger than 40 years, the proportion of seronegative individuals is similar to that in the general population. Vaccination should be considered for all patients positive for HCV infection. In persons older than 40 years with chronic liver disease, the decision to vaccinate for HAV should be made in the light of serological findings.

Brain endothelial adhesion molecule expression in experimental colitis

OBJECTIVES

1) To determine if endothelial expression of adhesion molecules involved in leukocyte recruitment is increased in the brain and other organs in four different models of experimental colitis, and 2) to investigate whether leukocyte infiltration occurs in the brain of colitic animals.

METHODS

Endothelial vascular cell adhesion molecule-1 (VCAM-1) and intercellular adhesion molecule-1 (ICAM-1) expression was quantified, using the dual radiolabeled antibody technique in rats with trinitrobenzenesulfonic acid (TNBS)-induced colitis, in mice with dextran sulfate sodium (DSS)-induced colitis, in SCID mice reconstituted with CD45RBhigh T-cells, and in IL-10-/- mice. Leukocyte infiltration in the brain of TNBS-induced colitic rats was assessed by myeloperoxidase activity and immunohistochemical staining with anti-CD45 monoclonal antibody.

RESULTS

Marked upregulation of brain endothelial VCAM-1 (2- to 5.5-fold) was consistently found in colitic animals in the four models studied. Brain VCAM-1 strongly correlated with colon VCAM-1 and colon weight. By contrast, upregulation of brain ICAM-1 in colitic animals was only observed in the CD45RBhigh transfer (3-fold) and the TNBS-induced (1.5-fold models). Heart and muscle VCAM-1 and ICAM-1 were not upregulated in colitic animals in the majority of models studied. There was no leukocyte infiltration into the brain of TNBS-induced colitic rats.

CONCLUSIONS

Our study demonstrates a marked and specific upregulation of endothelial VCAM-1 in the brain of colitic animals. This activation of cerebral endothelial cells was not associated with an infiltration of leukocytes into brain tissue.

Long-term follow-up of chronic hepatitis C in patients diagnosed at a tertiary-care center

BACKGROUND/AIMS

The natural history of chronic hepatitis C (HCV) is not completely understood. This study was aimed to evaluate the long-term outcome of the disease over a prolonged period of time and to identify factors associated with progression.

METHODS

One hundred and sixteen patients with non-cirrhotic chronic non-A, non-B hepatitis consecutively diagnosed at a tertiary hospital between 1971 and 1977 were followed until December 1998 or until death. Patients with significant alcohol intake were excluded from the study. Variables obtained at the time of diagnosis, including epidemiological, clinical, laboratory, and histological data were recorded to determine risk factors associated with the development of liver cirrhosis and hepatic decompensation.

RESULTS

Based on complete follow-up data, the development of liver cirrhosis and hepatic decompensation was evaluated in 94 and 114 of the 116 patients, respectively. Thirty-seven (39.3%) of 94 patients developed liver cirrhosis; an aspartate aminotransferase (AST) value higher than 70 IU/L was associated with development of cirrhosis (odds ratio (OR) 4.22, 95% CI 1.3-13.8). Hepatic decompensation occurred in 12 (10.5%) of 114 patients, its cumulative probability being 2.8% at 10 years, 5.2% at 15 years and 19.8% at 20 years. The only factor independently associated to the development of hepatic decompensation was the presence of fibrosis (stage 2 or 3) in the initial liver biopsy (OR 4.1, IC 95% 1.22-13.9). Liver-related death occurred only in seven (6%) of 114 patients. In comparison with the 116 patients diagnosed in the 1970's, patients with chronic hepatitis C diagnosed in 1999 were younger, more often asymptomatic, had lower AST and alanine aminotransferase (ALT) values and had significantly lower grade and stage histological scores.

CONCLUSIONS

In summary, chronic hepatitis C had a high rate of progression to liver cirrhosis over a prolonged follow-up. However, this might be related to the fact that two decades ago the diagnosis was made at a significantly more advanced stage of the disease. Patients at high risk of progression can be identified by biochemical and histological variables at the time of diagnosis.

Hydrocolonic sonography for evaluating inflammatory bowel disease

OBJECTIVE

The purpose of our study was to compare the usefulness of hydrocolonic sonography and (99m)Tc-hexamethylpropyleneamine oxime (HMPAO)--labeled leukocyte scintigraphy in the examination of patients with inflammatory bowel disease, using precise sonographic criteria of bowel involvement.

SUBJECTS AND METHODS

Sixty-eight consecutive patients with active inflammatory bowel disease (34 ulcerative colitis and 34 Crohn's disease), 12 with inactive inflammatory bowel disease, and 10 control subjects were prospectively studied. Patients with active disease underwent clinical assessment, hydrocolonic sonography, scintigraphy, and colonoscopy within 72 hr, whereas patients with inactive disease and control subjects underwent clinical examination and hydrocolonic sonography.

RESULTS

Involvement of a colonic segment by active inflammatory bowel disease was best defined by mucosal thickness greater than 1.5 mm, bowel wall thickness greater than 4 mm, mucosal irregularity, or the absence of haustra; and involvement of the terminal ileum by bowel wall thickness greater than 4 mm. Using these criteria, hydrocolonic sonography had 100% sensitivity for identifying patients with active inflammatory bowel disease and a greater overall accuracy (87%) than scintigraphy (77%) in the assessment of disease extension. In addition, strong correlation was shown between a hydrocolonic sonography activity index and clinical and endoscopic activity indexes.

CONCLUSION

This prospective study provides precise sonographic criteria for the definition of bowel involvement by active inflammatory bowel disease. Hydrocolonic sonography has a greater accuracy than scintigraphy for assessing disease extension and activity. Therefore, hydrocolonic sonography should be considered a first-choice technique to complete the study of inflammatory bowel disease after confirmation of the diagnosis by histology.

Brain endothelial adhesion molecule expression in experimental colitis

OBJECTIVES

1) To determine if endothelial expression of adhesion molecules involved in leukocyte recruitment is increased in the brain and other organs in four different models of experimental colitis, and 2) to investigate whether leukocyte infiltration occurs in the brain of colitic animals.

METHODS

Endothelial vascular cell adhesion molecule-1 (VCAM-1) and intercellular adhesion molecule-1 (ICAM-1) expression was quantified, using the dual radiolabeled antibody technique in rats with trinitrobenzenesulfonic acid (TNBS)-induced colitis, in mice with dextran sulfate sodium (DSS)-induced colitis, in SCID mice reconstituted with CD45RBhigh T-cells, and in IL-10-/- mice. Leukocyte infiltration in the brain of TNBS-induced colitic rats was assessed by myeloperoxidase activity and immunohistochemical staining with anti-CD45 monoclonal antibody.

RESULTS

Marked upregulation of brain endothelial VCAM-1 (2- to 5.5-fold) was consistently found in colitic animals in the four models studied. Brain VCAM-1 strongly correlated with colon VCAM-1 and colon weight. By contrast, upregulation of brain ICAM-1 in colitic animals was only observed in the CD45RBhigh transfer (3-fold) and the TNBS-induced (1.5-fold models). Heart and muscle VCAM-1 and ICAM-1 were not upregulated in colitic animals in the majority of models studied. There was no leukocyte infiltration into the brain of TNBS-induced colitic rats.

CONCLUSIONS

Our study demonstrates a marked and specific upregulation of endothelial VCAM-1 in the brain of colitic animals. This activation of cerebral endothelial cells was not associated with an infiltration of leukocytes into brain tissue.

Differential role of selectins in experimental colitis

BACKGROUND AND AIMS

The role of selectins in experimental colitis remains unknown. The aims of this study were to characterize the time-course expression of selectins in trinitrobenzene sulfonic acid (TNBS)-induced colitis, the functional role of selectins in colonic leukocyte-endothelial cell interactions, and the therapeutic usefulness of selectin blockade in this model.

METHODS

Control and TNBS-induced colitic rats were studied. Expression of P- and E-selectin was assessed by the radiolabeled antibody technique, and L-selectin by flow cytometry. Leukocyte-endothelial cell interactions were studied in colonic venules by using intravital microscopy under basal conditions and after P-, E-, or L-selectin immunoblockade. Additional groups of animals were treated with anti-P-selectin antibody, a nonbinding antibody, or dexamethasone, for 7 days.

RESULTS

P-selectin and E-selectin expression were markedly up-regulated in colitic rats. Increased leukocyte rolling was abrogated by anti-P-selectin, but only attenuated by anti-E- or anti-L-selectin antibodies. Only pretreatment with anti-P- selectin decreased leukocyte adhesion. Animals chronically treated with dexamethasone, but not with anti- P-selectin, had significantly lower macroscopic and histologic damage scores, colon weight, and myeloperoxidase (MPO) activity than those treated with nonbinding antibody.

CONCLUSIONS

P-selectin plays a key role on leukocyte rolling and its blockade attenuates leukocyte adhesion in TNBS-induced colitis. However, treatment with an anti-P-selectin antibody does not significantly improve colitis.