Strategies for detecting colon cancer and/or dysplasia in patients with inflammatory bowel disease.

BACKGROUND: Patients with longstanding ulcerative colitis and colonic Crohn's disease have an increased risk of colorectal cancer compared with the general population. This review assesses the evidence that endoscopic surveillance may prolong life by allowing earlier detection of colon cancer or its pre-cursor lesion, dysplasia, in patients with inflammatory bowel disease. OBJECTIVES: To assess the effectiveness of cancer surveillance programs in reducing the death rate from colorectal cancer in patients with ulcerative colitis and colonic Crohn's disease. SEARCH STRATEGY: The following strategies were used to identify relevant studies:1. MEDLINE and the Cochrane Central Register of Controlled Trials were searched from 1966 to August 2005. The medical subject headings "Ulcerative Colitis", "Crohn Disease" or "Inflammatory Bowel Disease" and "Surveillance" or "Cancer" were used to perform key-word searches of the databases.2. Hand searching of reference lists from papers. SELECTION CRITERIA: Potentially relevant articles were reviewed independently and unblinded by three authors to determine if they fulfilled the selection criteria. Each article was rated as being eligible, ineligible, or without sufficient information to determine eligibility. Any disagreement between reviewers was resolved by consensus. Any trials published in abstract form were only considered if it was possible to obtain full details of the protocol and results from the authors. DATA COLLECTION AND ANALYSIS: Eligible articles were reviewed in duplicate and the results of the primary research trials were abstracted onto specially designed data extraction forms. The proportion of patients dying from bowel cancer or other causes in the control and surveillance groups of each study was derived from life tables, survival curves or where possible, by calculating life tables from the data provided. Data from the original research articles were converted into 2x2 tables (survival versus death x surveillance versus control) for each of the individual studies for comparable follow-up intervals. The presence of significant heterogeneity among studies was tested by the chi-square test. Because this is a relatively insensitive test, a P value of less than 0.1 was considered statistically significant. Provided statistical heterogeneity was not present, the fixed effects model was used for the pooling of data. The 2x2 tables were combined into a summary test statistic using the pooled relative risk (RR) and 95% confidence intervals as described by Cochrane and Mantel and Haenszel. MAIN RESULTS: Karlen 1998a in a nested case-control study comprising 142 patients from a study population of 4664 UC patients, found that 2/40 patients dying of colorectal cancer had undergone surveillance colonoscopy on at least one occasion compared with 18/102 controls (RR 0.28, 95% CI 0.07 to 1.17). One of 40 patients who died from colorectal cancer had undergone surveillance colonoscopies on two or more occasions compared with 12/102 controls (RR 0.22, 95% CI 0.03 to 1.74) in contrast to a more modest effect observed for patients who had only one colonoscopy (RR 0.43, 95% CI 0.05 to 3.76). Choi 1993 found that carcinoma was detected at a significantly earlier stage in the surveilled patients; 15/19 had Duke's A or B carcinoma in the surveilled group compared to 9/22 in the non-surveilled group (P = 0.039). The 5-year survival rate was 77.2% for cancers occurring in the surveillance group and 36.3% for the no-surveillance group (P = 0.026). Four of 19 patients in the surveillance group died from colorectal cancer compared to 11 of 22 patients in the non-surveillance group (RR 0.42, 95% CI 0.16 to 1.11). Lashner 1990 found that four of 91 patients in a surveillance group died from colorectal cancer compared to 2 of 95 patients in a non-surveilled group (RR 2.09, 95% CI 0.39 to 11.12). Colectomy was less common in the surveillance group, 33 compared to 51 (P < 0.05) and was performed four years later (after 10 years of disease) in the surveillance group. For the pooled data analysis 8/110 patients in the surveillance group died from colorectal cancer compared to 13/117 patients in the non-surveillance group (RR 0.81, 95% CI 0.17 to 3.83). AUTHORS' CONCLUSIONS: There is no clear evidence that surveillance colonoscopy prolongs survival in patients with extensive colitis. There is evidence that cancers tend to be detected at an earlier stage in patients who are undergoing surveillance, and these patients have a correspondingly better prognosis, but lead-time bias could contribute substantially to this apparent benefit. There is indirect evidence that surveillance is likely to be effective at reducing the risk of death from IBD-associated colorectal cancer and indirect evidence that it may be acceptably cost-effective.

An investigation into the 'carry over' effect of neurostimulation in the treatment of angina pectoris.

Neurostimulation, by way of transcutaneous electrical nerve stimulation (TENS) and spinal cord stimulation, improves signs and symptoms of myocardial ischaemia, with evidence (from non-randomised studies) that this effect extends beyond the period of stimulation itself ('carry-over' effect). In this randomised controlled trial, 10 patients underwent baseline treadmill-exercise-testing (TET), followed by two further tests at fortnightly intervals. TENS was compared to placebo in a randomised fashion. TENS produced a significant increase in total exercise time (399.3 vs. 364.5 s, p < 0.05) and time to maximum ST depression (374 vs. 324 s, p = 0.01) without a significant difference in the maximum degree of ST depression (2.0 vs. 2.1 mm, p = NS). Rate-pressure product at peak exercise was not significantly different (197 vs. 193, p = NS). TENS produced a nonsignificant change in time to onset of angina (352 vs. 325 s, p = 0.07). Pre-treatment with TENS produces a significant improvement in exercise tolerance and measures of ischaemia but not significant improvement in symptoms.

Blockade of PAF receptors controls interleukin-8 production by regulating the activation of neutrophil CD11/CD18.

The production of interleukin-8 by neutrophils in response to particulate stimuli may play a role in the recruitment and activation of further neutrophils in an inflammatory reaction. Here, we have evaluated the sequence of early events leading to interleukin-8 production by phagocytosing neutrophils. Kinetic experiments showed that the phagocytosis of zymosan particles by human neutrophils was rapid in onset. In contrast, interleukin-8 production was more protracted and only detectable 6 h later. Nevertheless, inhibition of phagocytosis with cytochalasins B or D suppressed the late interleukin-8 production. Activation of neutrophils with zymosan failed to enhance CD11/CD18 expression on the neutrophil surface but led to an increase in the expression of an activation-dependent epitope on CD11/CD18. Pretreatment with the platelet-activating factor (PAF) receptor antagonist, UK-74505 (4-(2-chlorophenyl)-1,4-dihydro-3-ethoxycarbonyl-6-methyl-2-[4-(2-methylimidazol[4,5-c]pyrid-1-yl)phenyl]-5-[N-(2-pyridyl)carbamoyl]pyridine), significantly blocked the increase in the expression of the activation epitope, resulting in inhibition of the phagocytosis of zymosan and interleukin-8 production. In conclusion, the activation of neutrophils with zymosan leads to the activation of PAF receptors and this is followed by activation of CD11/CD18, phagocytosis of zymosan particles and subsequent interleukin-8 release.

Spinal cord stimulation significantly decreases the need for acute hospital admission for chest pain in patients with refractory angina pectoris.

OBJECTIVE: To assess the impact of spinal cord stimulation (SCS) on the need for acute admissions for chest pain in patients with refractory angina pectoris. DESIGN: Retrospective analysis of case records. PATIENTS: 19 consecutive patients implanted for SCS between 1987 and 1997. All had three vessel coronary disease, and all were in New York Heart Association functional group III/IV. METHODS: Admission rates were calculated for three separate periods: (1) from initial presentation up until last revascularisation; (2) from last revascularisation until SCS implantation; (3) from SCS implantation until the study date. Post-revascularisation rates were then compared with post-SCS rates, without including admissions before revascularisation, as this would bias against revascularisation procedures. RESULTS: Annual admission rate after revascularisation was 0.97/patient/year, compared with 0.27 after SCS (p = 0.02). Mean time in hospital/patient/year after revascularisation was 8.3 days v 2.5 days after SCS (p = 0.04). No unexplained new ECG changes were observed during follow up and patients presented with unstable angina and acute myocardial infarction in the usual way. CONCLUSIONS: SCS is effective in preventing hospital admissions in patients with refractory angina, without masking serious ischaemic symptoms or leading to silent infarction.

Differential regulation of eosinophil chemokine signaling via CCR3 and non-CCR3 pathways.

To investigate eosinophil stimulation by chemokines we developed a sensitive assay of leukocyte shape change, the gated autofluorescence/forward scatter assay. Leukocyte shape change responses are mediated through rearrangements of the cellular cytoskeleton in a dynamic process typically resulting in a polarized cell and are essential to the processes of leukocyte migration from the microcirculation into sites of inflammation. We examined the actions of the chemokines eotaxin, eotaxin-2, monocyte chemoattractant protein-1 (MCP-1), MCP-3, MCP-4, RANTES, macrophage inflammatory protein-1alpha (MIP-1alpha), and IL-8 on leukocytes in mixed cell suspensions and focused on the responses of eosinophils to C-C chemokines. Those chemokines acting on CCR3 induced a rapid shape change in eosinophils from all donors; of these, eotaxin and eotaxin-2 were the most potent. Responses to MCP-4 were qualitatively different, showing marked reversal of shape change responses with agonist concentration and duration of treatment. In contrast, MIP-1alpha induced a potent response in eosinophils from a small and previously undescribed subgroup of donors via a non-CCR3 pathway likely to be CCR1 mediated. Incubation of leukocytes at 37 degrees C for 90 min in the absence of extracellular calcium up-regulated responses to MCP-4 and MIP-1alpha in the majority of donors, and there was a small increase in responses to eotaxin. MIP-1alpha responsiveness in vivo may therefore be a function of both CCR1 expression levels and the regulated efficiency of coupling to intracellular signaling pathways. The observed up-regulation of MIP-1alpha signaling via non-CCR3 pathways may play a role in eosinophil recruitment in inflammatory states such as occurs in the asthmatic lung.

Cloning and characterization of the guinea pig eosinophil eotaxin receptor, C-C chemokine receptor-3: blockade using a monoclonal antibody in vivo.

Certain C-C chemokines, signaling via the eotaxin receptor C-C chemokine receptor-3 (CCR3), are thought to be central mediators of eosinophil accumulation in allergic inflammation. To investigate the role of CCR3 in vivo, we cloned the guinea pig eotaxin receptor (guinea pig CCR3) from a genomic DNA library. We isolated a single-exon open reading frame coding for a 358-amino acid chemokine receptor protein with 67 and 69% homology to human and murine CCR3, respectively. When expressed in stable transfectants, this receptor bound 125I-labeled guinea pig eotaxin, 125I-labeled human monocyte chemotactic protein-3, and 125I-labeled human RANTES. In chemotaxis assays, guinea pig CCR3 transfectants responded only to guinea pig eotaxin, with a maximal effect at 100 nM. mAbs were raised that bound selectively to both guinea pig CCR3 transfectants and guinea pig eosinophils. One of these mAbs, 2A8, blocked both ligand binding to transfectants and their chemotaxis in response to eotaxin. The Ab also inhibited chemotaxis and the elevation of cytosolic calcium in guinea pig eosinophils in response to eotaxin. F(ab')2 fragments of 2A8 were prepared that retained the ability to inhibit eosinophil calcium responses to eotaxin. Pretreatment of (111)In-labeled eosinophils in vitro with F(ab')2 2A8 selectively inhibited their accumulation in response to eotaxin in vivo. These data demonstrate that functional blockade of eosinophil chemokine receptors can be achieved in vivo and provide further support for the development of novel anti-inflammatory drugs targeting eosinophil recruitment through chemokine receptor antagonism.

Mechanisms of acute eosinophil mobilization from the bone marrow stimulated by interleukin 5: the role of specific adhesion molecules and phosphatidylinositol 3-kinase.

Mobilization of bone marrow eosinophils is a critical early step in their trafficking to the lung during allergic inflammatory reactions. We have shown previously that the cytokine interleukin (IL)-5, generated during an allergic inflammatory reaction in the guinea pig, acts systemically to mobilize eosinophils from the bone marrow. Here, we have investigated the mechanisms underlying this release process. Examination by light and electron microscopy revealed the rapid migration of eosinophils from the hematopoietic compartment and across the bone marrow sinus endothelium in response to IL-5. Using an in situ perfusion system of the guinea pig hind limb, we showed that IL-5 stimulated a dose-dependent selective release of eosinophils from the bone marrow. Eosinophils released from the bone marrow in response to IL-5 expressed increased levels of beta2 integrin and a decrease in L-selectin, but no change in alpha4 integrin levels. A beta2 integrin-blocking antibody markedly inhibited the mobilization of eosinophils from the bone marrow stimulated by IL-5. In contrast, an alpha4 integrin blocking antibody increased the rate of eosinophil mobilization induced by IL-5. In vitro we demonstrated that IL-5 stimulates the selective chemokinesis of bone marrow eosinophils, a process markedly inhibited by two structurally distinct inhibitors of phosphatidylinositol 3-kinase, wortmannin and LY294002. Wortmannin was also shown to block eosinophil release induced by IL-5 in the perfused bone marrow system. The parallel observations on the bone marrow eosinophil release process and responses in isolated eosinophils in vitro suggest that eosinophil chemokinesis is the driving force for release in vivo and that this release process is regulated by alpha4 and beta2 integrins acting in opposite directions.

Myocardial contractility is not constant during spontaneous atrial fibrillation in patients.

BACKGROUND: The variation in stroke volume and pulse pressure characteristic of atrial fibrillation is usually ascribed to time-dependent ventricular filling, implying a single positive relationship between end-systolic pressure and volume, which defines a single state of myocardial contractility. We tested the hypothesis that contractility also varies. METHODS AND RESULTS: We measured the left ventricular pressure and volume continuously with a conductance catheter with catheter-tip micromanometer introduced retrogradely into the left ventricle. The end-systolic pressure-volume relationship was determined in 6 patients in atrial fibrillation undergoing cardiac catheterization for diagnostic purposes and 4 control patients in sinus rhythm undergoing coronary artery bypass graft surgery. The normal positive relationship between end-systolic pressure and volume was found in the control patients, but no such positive relationship was found in any patient in atrial fibrillation. In the latter, the slopes of the linear regressions were either not significantly different from zero or significantly negative (r values <0.08), both results indicating a change in contractility from beat to beat. Significantly negative relationships were found between end-systolic volume and preceding R-R interval (-0.82

Eotaxin induces a rapid release of eosinophils and their progenitors from the bone marrow.

The CC-chemokine eotaxin is a potent eosinophil chemoattractant that stimulates recruitment of eosinophils from the blood to sites of allergic inflammation. Mobilization from the bone marrow is an important early step in eosinophil trafficking during the allergic inflammatory response. In this paper we examine the potential of eotaxin to mobilize eosinophils and their progenitors from bone marrow. Eotaxin stimulated selective, dose-dependent chemotaxis of guinea pig bone marrow eosinophils in vitro. Intravenous injection of eotaxin (1 nmol/kg) into guinea pigs in vivo stimulated a rapid blood eosinophilia (from 3.9 +/- 1.2 to 28 +/- 9.9 x 10(4) eosinophils/mL at 30 minutes) and a corresponding decrease in the number of eosinophils retained in the femoral marrow (from 9.0 +/- 0. 8 to 4.8 +/- 0.8 x 10(6) eosinophils per femur). To show a direct release of eosinophils from the bone marrow an in situ perfusion system of the guinea pig femoral bone marrow was developed. Infusion of eotaxin into the arterial supply of the perfused femoral marrow stimulated a rapid and selective release of eosinophils into the draining vein. In addition, eotaxin stimulated the release of colony-forming progenitor cells. The cytokine interleukin-5 was chemokinetic for bone marrow eosinophils and exhibited a marked synergism with eotaxin with respect to mobilization of mature eosinophils from the femoral marrow. Thus, eotaxin may be involved in both the mobilization of eosinophils and their progenitors from the bone marrow into the blood and in their subsequent recruitment into sites of allergic inflammation.

Blockade of chemokine activity by a soluble chemokine binding protein from vaccinia virus.

Chemokines direct migration of immune cells into sites of inflammation and infection. Chemokine receptors are seven-transmembrane domain proteins that, in contrast to other cytokine receptors, cannot be easily engineered as soluble chemokine inhibitors. Poxviruses encode several soluble cytokine receptors to evade immune surveillance, providing new strategies for immune modulation. Here we show that vaccinia virus and other orthopoxviruses (cowpox and camelpox) express a secreted 35-kDa chemokine binding protein (vCKBP) with no sequence similarity to known cellular chemokine receptors. The vCKBP binds CC, but not CXC or C, chemokines with high affinity (Kd = 0.1-15 nM for different CC chemokines), blocks the interaction of chemokines with cellular receptors, and inhibits chemokine-induced elevation of intracellular calcium levels and cell migration in vitro, thus representing a soluble inhibitor that binds and sequesters chemokines. The potential of vCKBP as a therapeutic agent in vivo was illustrated in a guinea pig skin model by the blockade of eotaxin-induced eosinophil infiltration. a feature of allergic inflammatory reactions. Furthermore, vCKBP may enable the rational design of antagonists to neutralize pathogens that use chemokine receptors to initiate infection, such as HIV or the malarial parasite.

Effect of PDE4 inhibitors on zymosan-induced IL-8 release from human neutrophils: synergism with prostanoids and salbutamol.

1. The activation of neutrophils with particulate stimuli such as zymosan induces the generation of the C-X-C chemokine interleukin (IL)-8. There is evidence that neutrophil derived IL-8 plays an important role in human diseases such as the adult respiratory distress syndrome. In the present study, we examined the effects of cyclic AMP elevating agents on the ability of human neutrophils to generate IL-8 in response to zymosan particles. 2. The PDE4 inhibitor rolipram had limited effect on zymosan-induced IL-8 generation. In contrast, the PDE4 inhibitors RP 73401 and SB 207499 concentration-dependently suppressed IL-8 generation. The potency of these inhibitors was RP 73401 > SB 207499 > rolipram which is correlated with their rank order of potency at inhibiting the catalytic site of purified neutrophil PDE4. Pretreatment of neutrophils with the PDE3 inhibitor ORG 9935 or the PDE5 inhibitor zaprinast had no effect on IL-8 generation. 3. The prostanoids prostaglandin E1 (PGE1) and PGE2 inhibited zymosan-induced IL-8 release from neutrophils in a dose-dependent manner, in response to 10(-5) M PGE1 and PGE2 inhibiting IL-8 generation by 89% and 75%, respectively. Similarly, the beta2-adrenoceptor agonist salbutamol also inhibited IL-8 generation, but it was less effective than the prostanoids. 4. Significant synergism between prostanoids or salbutamol and the PDE4 inhibitors to inhibit IL-8 generation was observed. In contrast, there was no significant synergism between PGE2 and the PDE3 inhibitor ORG 9935 or the PDE5 inhibitor zaprinast. 5. In order to evaluate the potential role of protein kinase A in mediating the inhibitory effects of cyclic AMP-elevating agents, we used the protein kinase A inhibitors, H 89 and KT 5720. Pretreatment of neutrophils with these drugs completely reversed the inhibitory effects of a combination treatment with rolipram and PGE2 on zymosan-induced IL-8 release. 6. Microscopic examination revealed that most neutrophils contained one or more zymosan particles and that combination treatment with rolipram and PGE2 noticeably reduced the number of ingested particles. Moreover, there was a significant reduction in the percentage of neutrophils which ingested three or more zymosan particles. 7. Thus, our results demonstrate that cyclic AMP-elevating agents modulate the ability of neutrophils to generate IL-8 in response to a particulate stimulus. However, these agents also modulate the ability of neutrophils to phagocytose zymosan particles. Whether this effect will translate into inhibition of the ability of neutrophils to deal with infectious agents needs to be investigated further.

Angiogenic and HIV-inhibitory functions of KSHV-encoded chemokines.

Unique among known human herpesviruses, Kaposi's sarcoma-associated herpesvirus (KSHV or HHV-8) encodes chemokine-like proteins (vMIP-I and vMIP-II). vMIP-II was shown to block infection of human immunodeficiency virus-type 1 (HIV-1) on a CD4-positive cell line expressing CCR3 and to a lesser extent on one expressing CCR5, whereas both vMIP-I and vMIP-II partially inhibited HIV infection of peripheral blood mononuclear cells. Like eotaxin, vMIP-II activated and chemoattracted human eosinophils by way of CCR3. vMIP-I and vMIP-II, but not cellular MIP-1alpha or RANTES, were highly angiogenic in the chorioallantoic assay, suggesting a possible pathogenic role in Kaposi's sarcoma.

Chemoattractant cross-desensitization of the human neutrophil IL-8 receptor involves receptor internalization and differential receptor subtype regulation.

Human neutrophils undergo rapid homologous receptor desensitization following repeated stimulation with chemoattractants such as IL-8, C5a, and FMLP. It has also been demonstrated that cross-desensitization among these chemoattractant receptors occurs. We investigated the mechanisms underlying the cross-desensitization of responses to IL-8 induced by pretreatment with FMLP or C5a. In [125I]-labeled IL-8 binding studies we found that the cross-desensitization induced by FMLP or C5a was associated with a subsequent reduction in IL-8 binding to neutrophils. There was no recovery of [125I]-labeled IL-8 binding on removal of the C5a or FMLP pretreatment. FACS analysis using mAbs specific for the two IL-8R subtypes showed differential regulation of IL-8R A and IL-8R B cell surface expression after chemoattractant pretreatment. Homologous desensitization by IL-8 resulted in internalization of IL-8R A and IL-8R B, but only IL-8R A was completely re-expressed after removal of agonist. FMLP stimulation led to a substantial loss of IL-8R B from the cell surface, whereas C5a stimulation induced only a partial loss. In both cases there was no re-expression of IL-8R B on removal of the chemoattractant stimulation. C5a and FMLP did not affect IL-8R A expression. Calcium mobilization studies using melanoma growth stimulatory activity and IL-8 suggest that a sustained loss of IL-8R B may play a part in maintaining FMLP-induced IL-8R cross-desensitization. Chemoattractant-induced cross-desensitization of neutrophils may be of importance in regulating neutrophil accumulation during the inflammatory response in vivo.