A47 THE GUT MICROBIOTA INFLUENCES COLONIC HEALING AFTER SURGERY IN PATIENTS UNDERGOING BOWEL RESECTION FOR COLORECTAL CANCER

Background

The standard treatment of colorectal cancer (CRC) consists of a surgical resection of the colonic segment with the tumor, followed by a reconnection of the remaining bowel ends, or "anastomosis". The anastomosis may fail to heal in up to 20% of patients, which leads to anastomotic leak, a major complication that increases postoperative morbidity and mortality. This complication is unpredictable and its causes remain poorly understood.

Purpose

The objective of this study is to investigate the possible role of the gut microbiome in anastomotic healing after surgery in patients with CRC.

Method

We collected preoperative fecal samples and intraoperative mucosal samples from CRC patients undergoing surgery with anastomosis. The gut microbiota of patients with AL and of others that presented optimal healing after surgery was analyzed and compared using the Anchor 16S pipeline. To assess the role of the patients' microbiota in healing, fecal microbiota transplantation (FMT) was performed in mice using preoperative fecal samples from CRC patients with and without AL. Mice were then subjected to colonic surgery using a colonic anastomosis model. Six days after surgery, anastomotic healing was assessed macroscopically and microscopically. The gut barrier function was also assessed. The gut microbiota composition was compared between the groups colonized with samples from patients with and without AL to detect potential differences.

Result(s)

Mice colonized by FMT with the microbiota of donors with AL displayed poor anastomotic healing macroscopically, and a weaker wound microscopically. These same mice displayed a weaker gut barrier, as objectified by higher bacterial translocation to the spleen. The anastomoses of mice receiving the microbiota of AL donors displayed lower concentrations of collagen and fibronectin and higher inflammatory cytokines and collagenolytic enzymes, indicating poor extracellular matrix formation and collagen degradation locally.The beta-diversity of the gut microbiota was significantly different between mice receiving the microbiota of donors with and without AL, and several bacterial species were differentially abundant between the two groups.

Conclusion(s)

The preoperative gut microbiota in CRC patients who experience anastomotic leak after surgery induces poor anastomotic healing in mice and a weaker gut barrier after colonic surgery. Several bacterial species were found to be associated with the healing process.

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CIHR, Other

Please indicate your source of funding;

NSERC, FRQS, New Frontiers in Research, Montreal Cancer Institute.

Disclosure of Interest

None Declared

Informatics Methodologies for Evaluation Research in the Practice Setting

A continuing challenge in health informatics and health evaluation is to enable access to the practice of health care so that the determinants of successful care and good health outcomes can be measured, evaluated and analysed. Furthermore the results of the analysis should be available to the health care practitioner or to the patient as might be appropriate, so that he or she can use this information for continual improvement of practice and optimisation of outcomes. In this paper we review two experiences, one in primary care, the FAMUS project, and the other in hospital care, the Autocontrol project. Each project demonstrates an informatics approach for evaluation research in the clinical setting and indicates ways in which useful information can be obtained which with appropriate feed-back and education can be used towards the achievement of better health. Emphasis is given to data collection methods compatible with practice and to high quality information feedback, particularly in the team context, to enable the formulation of strategies for practice improvement.

Antiphospholipid antibody-mediated effects in an arterial model of thrombosis are dependent on Toll-like receptor 4

Patients with antiphospholipid syndrome (APS) produce antiphospholipid antibodies (aPL) and develop vascular thrombosis that may occur in large or small vessels in the arterial or venous beds. On the other hand, many individuals produce aPL and yet never develop thrombotic events. Toll-like receptor 4 (TLR4) appears to be necessary for aPL-mediated prothrombotic effects in venous and microvascular models of thrombosis, but its role in arterial thrombosis has not been studied. Here, we propose that aPL alone are insufficient to cause thrombotic events in an arterial model of APS, and that a concomitant trigger of innate immunity (e.g. TLR4 activation) is required. We show specifically that anti-β2-glycoprotein I (anti-β2GPI) antibodies, a subset of aPL, accelerated thrombus formation in C57BL/6 wild-type, but not TLR4-deficient, mice in a ferric chloride-induced carotid artery injury model. These aPL bound to arterial and venous endothelial cells, particularly in the presence of β2GPI, and to human TLR4 by enzyme-linked immunoassay. Arterial endothelium from aPL-treated mice had enhanced leukocyte adhesion, compared to control IgG-treated mice. In addition, aPL treatment of mice enhanced expression of tissue factor (TF) in leukocytes induced by the TLR4 ligand lipopolysaccharide (LPS). aPL also enhanced LPS-induced TF expression in human leukocytes in vitro. Our findings support a mechanism in which aPL enhance TF expression by leukocytes, as well as augment adhesion of leukocytes to the arterial endothelium. The activation of TLR4 in aPL-positive individuals may be required to trigger thrombotic events.

The dual role of innate immunity in antiphospholipid syndrome and systemic lupus erythematosus

Antiphospholipid syndrome (APS), as a primary disease or a secondary syndrome in systemic lupus erythematosus (SLE), is characterized by the presence of antiphospholipid antibodies (aPL) and a clinical event. It is likely that both genetic and environmental factors lead to the development of aPL and progression to disease. However, the precise mechanisms are not known. We hypothesize that innate immune activation plays a dual role in APS and SLE, both in the production of aPL (i.e. “initiation” phase) and in the development of a clinical event (i.e. “effector” phase). We have shown that mice immunized with certain phospholipid-binding proteins (e.g. β2-glycoprotein I (β2GPI)), plus a concomitant trigger of innate immunity (e.g. a toll-like receptor 4 (TLR4) ligand), produce a strong β2GPI-reactive T cell response, resulting in high levels of aPL as well as other SLE autoantibodies. We propose that β2GPI, through its interaction with apoptotic cells, permits B cell epitope spread to multiple SLE autoantibodies. Innate immune activation is also implicated in a murine model of aPL-enhanced thrombus formation. This dual role of innate immune activation provides new insight into the mechanisms involved in the initiation of aPL and other SLE-related autoantibodies, as well as the development of aPL-mediated disease.

Phospholipid-binding proteins differ in their capacity to induce autoantibodies and murine systemic lupus erythematosus

We have previously shown that immunization of nonautoimmune mice with the phospholipid-binding protein β2-glycoprotein I (β2GPI), in combination with lipopolysaccharide (LPS), induces a murine model of systemic lupus erythematosus (SLE), with sequential emergence of autoantibodies and glomerulonephritis. Here, we determine whether the paradigm for induction of murine SLE extends to other phospholipid-binding proteins. Mice were immunized with a phospholipid-binding protein (prothrombin (PT), protein S, or β2GPI), or a nonphospholipid-binding protein (glu-plasminogen), in the presence of LPS. The breadth and degree of the autoantibody response, and the frequency of glomerulonephritis, varied among the three proteins, with β2GPI being the most effective in inducing SLE-like disease. The phospholipid-binding proteins also differed in the pattern of serum cytokines they elicited. The most apparent difference between β2GPI and the other phospholipid-binding proteins was in their ability to bind to LPS: β2GPI bound to LPS, while PT and protein S did not. Our data suggest that binding to phospholipid(s) is a necessary, but not sufficient, condition for full induction of murine SLE. We propose that other properties, such as physiologic function, avidity for anionic phospholipids, and degree of interaction with other cell surface and/or circulating molecules (particularly LPS) may determine the range and severity of disease.

Endothelial apoptosis and chronic transplant vasculopathy: recent results, novel mechanisms

Chronic transplant vasculopathy (CTV) is a progressive form of vascular obliteration affecting the arteries, arterioles and capillaries of solid organ transplants. It is characterized by intimal accumulation of mononuclear cells, vascular smooth muscle cells (VSMC), myofibroblasts and connective tissue. Mounting evidence, based on animal models and human biopsy results, suggests that acute and persistent rejection triggering apoptosis of endothelial cells (EC) plays a pivotal role in CTV. The precise mechanisms that underlie the induction of fibroproliferative changes in association with endothelial apoptosis have yet to be clearly delineated. Recent observations in the field of apoptosis research provide some important mechanistic clues. First, endothelial apoptosis creates a state of hyperadhesiveness for mononuclear cells, thus facilitating sustained leukocyte infiltration. Second, phosphatidylserine-dependent engulfment of apoptotic cells by infiltrating mononuclear leukocytes promotes transforming growth factor-beta1 production. Third, apoptosis of EC triggers extracellular matrix (ECM) proteolysis thus initiating the production of fibroproliferative/fibrogenic ECM fragments. The relative importance of these mechanisms in the pathophysiology of CTV will need to be addressed in vivo. Yet, these recent developments provide a new mechanistic framework that will help better define the importance of immune-mediated EC apoptosis in the regulation of vascular repair.

Dyslipidemias and the primary prevention of cardiovascular disease: analysis of the FAMUS primary care register

BACKGROUND

Primary prevention of cardiovascular disease with a pharmacological approach to dyslipidemias is controversial. Little is known about the clinical management by general practitioners in this area.

OBJECTIVES

To evaluate the patterns of treatment of patients in primary prevention who were entered in the FAmily Medicine, Université de Sherbrooke (FAMUS) register and to calculate the probability of their receiving a hypolipidemic agent according to the presence of various risk profiles.

PATIENTS AND METHODS

Descriptive study based on the FAMUS prospective primary care register. Data from patients in primary prevention (those who had not sustained a cardiovascular event) were extracted and analyzed.

MAIN RESULTS

Of the 52,505 patients in the register, 48, 190 were identified as being in primary prevention. Of these, 22,250 (46.2%) had a complete lipid profile on record, and 2300 had received a prescription for a hypolipidemic agent (4.8%). Patients under pharmacological treatment had significantly higher lipid values. The adjusted relative risk of being treated with a hypolipidemic agent was 1.3 for smokers, 1.3 for diabetic patients, 2.0 for those with a positive family history of premature cardiovascular disease, 2.2 for hypertensives and 3.3 for men over 45 years of age or women over 55 years, compared with patients who were not taking lipid-lowering medications. The number of risk factors was even more strongly associated with the probability of being treated.

CONCLUSION

Overall, few patients in primary prevention in the register were treated with a pharmacological agent. The presence of associated risk factors in this study was an important predictor for treatment, suggesting that patients in primary prevention are being evaluated globally as a function of all of their risk factors, not just their lipid and lipoprotein levels. Further attention, nonetheless, needs to be directed to the segment of the population with multiple risk factors whose lipoprotein profile is unknown or who are not being treated to guideline target levels.

Antiplatelet and lipid-lowering therapies for the secondary prevention of cardiovascular disease: are we doing enough?

OBJECTIVE

To evaluate whether current recommendations with respect to the treatment of dyslipidemias and the use of antiplatelet agents are being applied in the secondary prevention of cardiovascular disease in primary care settings.

DESIGN

Descriptive study based on data from the FAMUS (FAmily Medicine, Université de Sherbrooke) primary care register.

SETTING AND PARTICIPANTS

Two-hundred and thirty-three physicians participating in the FAMUS project contributed information from nonpregnant patients over 20 years of age consulting for a periodic health examination between 1992 and 1996.

INTERVENTIONS

Data from patients in secondary prevention (those with or having had angina, a previous myocardial infarction, bypass surgery, coronary angioplasty or peripheral vascular disease) were extracted and analyzed.

MAIN RESULTS

Of the 52,505 patients in the register, 4315 (8%) were identified as being in secondary prevention. Overall, 53% were noted as receiving an antiplatelet agent while 4% were taking warfarin therapy. Only 64% (2780) had a complete lipid profile on record while 38% were being treated with a hypolipidemic agent. In the treated group, only 30% had a low density lipoprotein cholesterol level below 3.0 mmol/L compared with 22% in the untreated group.

CONCLUSIONS

A large number of patients identified as being in secondary prevention were not screened for dyslipidemias, and, of those who were, the majority were undertreated according to current recommendations. Antiplatelet agents were more widely prescribed but potentially underused.

Informatics methodologies for evaluation research in the practice setting

A continuing challenge in health informatics and health evaluation is to enable access to the practice of health care so that the determinants of successful care and good health outcomes can be measured, evaluated and analysed. Furthermore the results of the analysis should be available to the health care practitioner or to the patient as might be appropriate, so that he or she can use this information for continual improvement of practice and optimisation of outcomes. In this paper we review two experiences, one in primary care, the FAMUS project, and the other in hospital care, the Autocontrol project. Each project demonstrates an informatics approach for evaluation research in the clinical setting and indicates ways in which useful information can be obtained which with appropriate feed-back and education can be used towards the achievement of better health. Emphasis is given to data collection methods compatible with practice and to high quality information feedback, particularly in the team context, to enable the formulation of strategies for practice improvement.

[Treatment patterns of hypertension in 1996. Data from the Quebec Family Practice, University of Sherbrooke registry]

OBJECTIVE

To describe the treatment of hypertension, alone or in combination with associated conditions, by a group of general practitioners in the FAMUS network and to compare these treatment patterns to the recommendations of the Canadian Hypertension Society Consensus.

DESIGN

Descriptive study based on data collected by 233 physicians in the FAMUS provincial register on hypertensive patients treated in 1996.

PARTICIPANTS

Developed between 1992 and 1996, the register contains 52,505 patients, 9,094 of whom have high blood pressure. These patients consulted their general practitioners for a complete examination. The data concern the risk factors for cardiovascular disease and include the list of medications prescribed.

MAIN OUTCOME MEASURES

Evaluation of the proportions in which various classes of medications were prescribed, and the most common combinations in relation to the presence or absence of associated conditions.

RESULTS

Of the 4,049 hypertensive patients seen in 1996, 50.2% were treated with one medication; 32.9% were treated with more than one medication; and 16.9% received no antihypertensive medication. The most frequently prescribed medications were calcium channel blockers (26.1%), followed by diuretics (25.3%), angiotensin-converting enzyme inhibitors (24.3%), and beta-blockers (20.0%). Other agents made up the remaining 4.3% of prescriptions. The proportions were similar for patients without complications who received one medication.

CONCLUSIONS

Results of this study suggest that the new molecules are widely used and that treatment patterns differ from the recommendations of the Canadian Hypertension Society Consensus, particularly in the absence of associated conditions.

Excitatory and inhibitory amino acids in the cerebral cortex of nucleus basalis magnocellularis lesioned rats

It is well known that pathways arising from the nucleus basalis magnocellularis in the basal forebrain which terminate in the cerebral cortex are involved in cognitive function. The cholinergic system is generally thought to play a large part in these processes from lesion, pharmacological and transplantation studies. With increasing evidence suggesting the involvement of amino acid transmitters in learning and memory processes, it is of interest to also evaluate possible changes in the levels of amino acid transmitters in the cortex of nucleus basalis magnocellularis-lesioned rats. In the present study, 9 cortical amino acids were measured in rats with bilateral lesions of the nucleus basalis magnocellularis. We measured significant reductions in aspartate, alanine and gamma-aminobutyric acid; these were 80%, 75%, and 81%, respectively, of control brain values. These results suggest that changes in the amino acid content of the cerebral cortex following lesion of the nucleus basalis magnocellularis-lesioned rat should perhaps also be considered when evaluating behavioral effects in this model.

Hypercholesterolaemia in childhood: repercussions in adulthood

The development of atherosclerotic vascular disease is influenced by multiple factors present since early age. Abnormal lipid metabolism, a major cause of atherosclerosis, results from genetic predisposition and is influenced by a variety of exogenous conditions. This article reviews the published studies of serum cholesterol tracking. The Sherbrooke cohort study on serum cholesterol tracking from early infancy to adolescence is described. The role of dietary habits, nutrient intake and other lifestyle-associated factors are scrutinized. Finally, a family-oriented detection of coronary risk factors in adolescence is discussed with emphasis on the future implementation of new genetic techniques.

Comparison of subcutaneous and intravenous recombinant human erythropoietin for anemia in hemodialysis patients with significant comorbid disease

While recombinant human erythropoietin (rHuEPO) is an effective therapy for anemia in renal failure, most published studies concern benefits in relatively healthy hemodialysis patients. The present study compares intravenous and subcutaneous administration of rHuEPO in an unselected group of 128 hemodialysis patients who were randomized to receive rHuEPO in an initial dose of 150 U/kg/week in three divided doses by subcutaneous or intravenous injection. Following a 4-week placebo run-in period, patients received rHuEPO until their hemoglobin was stable between 105 and 125 g/l for 4 weeks and then followed for a further 24 weeks. Eighty-three patients completed the study, 45 in the subcutaneous and 38 in the intravenous group. There was no difference in mean hemoglobin at any stage between subcutaneous and intravenous patients. Mean rHuEPO dose at the time of stabilization was significantly lower in the subcutaneous group compared to the intravenous (205.9 +/- 135.4 vs. 274.1 +/- 142.4 U/kg/week; p = 0.019), mean time to hemoglobin target was 9.9 +/- 4.5 weeks for the subcutaneous group and 11.9 +/- 4.9 weeks for the intravenous group (p = 0.037). Time to stabilization was 14.9 +/- 4.7 weeks for the subcutaneous compared to 17.3 +/- 3.9 weeks for the intravenous group (p = 0.006). Diabetic patients had higher dose requirements for rHuEPO at all time points and required a longer time to reach stabilization than nondiabetics (18.6 +/- 4.6 vs. 15.6 +/- 4.3 weeks; p = 0.016). Quality of life estimated by a disease-specific Kidney Disease Questionnaire improved significantly during rHuEPO therapy in both groups. There was no significant change in dialysis prescription throughout the study.(ABSTRACT TRUNCATED AT 250 WORDS)

The Couvade Syndrome: The biological, psychological, and social impact of pregnancy on the expectant father

The Couvade syndrome describes the various physical symptoms found in expectant fathers. In this descriptive study, we have attempted to determine the extent to which this syndrome occurs among expectant fathers in Quebec, identify certain risk factors, and observe the repercussions of pregnancy on the social and family behaviour of the expectant father, as well as on the use of health care services.

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The couvade syndrome describes the various physical symptoms found in expectant fathers. In this descriptive study, we have attempted 1) to determine the extent to which this syndrome occurs among expectant fathers in Quebec, 2) to identify certain risk factors, and 3) to observe the repercussions of pregnancy on the social and family behaviour of the expectant father as well as on the use of health care services. Within four days of delivery, a group of thirty-one fathers completed a multiple-choice questionnaire during an individual interview. Sixty-one per cent reported at least one of twenty-eight physical symptoms listed. It would also appear that the men's relationship with their own father before the age of 12 had an impact on the development of the syndrome.

A progressive neurological syndrome associated with an isolated vitamin E deficiency

Several authors have recently reported a neurological disorder associated with chronic vitamin E deficiency in man. Except in one patient, this deficiency has always been secondary to an underlying disease resulting in lipid malabsorption. We report a second case of such a neurological syndrome in a patient in whom vitamin E deficiency was an isolated finding. The clinical picture in our patient was characterized by a diffuse muscle weakness most prominent distally and in the lower limbs, generalized areflexia, a decrease in proprioception and vibration sense and slight limb and gait ataxia. His condition improved on alpha tocopherol therapy so that it is very likely that vitamin E deficiency is responsible for his neurological deficit. Since in our patient as well as in several other reported cases this condition has been treatable, it is important that this syndrome be recognized in children presenting a suggestive clinical picture even if they do not have lipid malabsorption.

Headache as an epileptic manifestation

In two cases, depth electrode studies and behavioral recordings indicated that headache was a clinical manifestation of ictal activity. The epileptogenic focus was found in the right limbic system, and right temporal lobectomy relieved the headaches.