Enhanced expression of P-selectin (CD62P) by endothelial cells seeded onto synthetic arterial prostheses (PET, Dacron) is correlated with leukocyte interactions.

This study evaluated the expression by seeded endothelial cells (S-EC) of P-selectin (CD62P/GMP-140/PADGEM), an adhesion molecule implicated in endothelial-leukocyte interactions. Endothelial cells were seeded onto knitted polyethylene terephthalate (PET, Dacron(R)) prostheses and compared with control endothelial cells (C-EC) cultured in flasks to the same stage. Using flow cytometry techniques, we observed that CD62P expression by PET S-EC was significantly increased (p<0.05) compared to C-EC. Moreover, RT PCR techniques showed that the CD62P RNA level was higher on S-ECs compared to C-ECs. Following adhesion assays, increased polymorphonuclear neutrophil (PMN) attachment to the PET-seeded prostheses as compared to control cultures (p<0.001) was observed. PMN adherence was enhanced by TNFalpha activation. PMN adhesion was decreased significantly (p<0.001) after the incubation of resting EC or TNFalpha-activated EC-seeded prostheses with a blocking monoclonal antibody (LYP20) directed against the P-selectin. Such results suggest that: (1) PET prosthetic material may induce the expression of P-selectin by S-EC; (2) seeding conditions provoke an increase in PMN adhesion; (3) increased PMN interactions with seeded PET material is partially dependent upon P-selectin expression by the S-EC.

Troponin I, troponin T, or creatine kinase-MB to detect perioperative myocardial damage after coronary artery bypass surgery.

STUDY OBJECTIVES: To compare cardiac troponin I (cTnI), cardiac troponin T (cTnT), and creatine kinase MB (CKMB mass) in patients with and without new Q wave on the ECG following coronary artery bypass graft (CABG) surgery. PATIENTS: After ethic committee's approval and informed consent, 82 patients, mean age 63+/-10 years, scheduled for CABG were included. INTERVENTIONS: Arterial blood samples were drawn during cardiopulmonary bypass, before, and 6, 12, 24, and 48 h after aortic cross-clamp release. cTnI, cTnT, and CKMB mass were measured. The appearance of new Q wave on the ECG performed preoperatively and 24 h postoperatively was used to assess myocardial lesion independently of biological markers. RESULTS: There were 69 patients without new Q wave on the ECG (group 1) and 13 with (group 2). In group 1, cTnI reached a peak of 2.1 microg/L (median, interquartile range [IQ]=2.4) at 12 h, cTnT increased progressively with a peak of 0.22 microg/L (IQ=0.2) at 48 h, and CKMB presented an earlier peak of 10 microg/L (IQ=6.2) at 6 h. Starting with the same median value, group 2 patients presented significantly higher peaks: cTnI: 17 microg/L (IQ=16) at 12 h; cTnT: 1.4 microg/L (IQ=2.3) at 12 h; and CKMB mass: 74 microg/L (IQ=61) at 6 h. Receiver operating characteristic (ROC) curves were constructed. The area under the curve was 0.90 for cTnI, 0.84 for CKMB, and 0.81 for cTnT (not significant). The best cutoff values to discriminate between group 1 and group 2 patients were determined with the ROC curves: cTnI=5 microg/L; CKMB mass=20 microg/L; cTnT=0.3 microg/L. Sensitivity, specificity, and positive and negative values for cTnI (5 microg/L) were 91%, 82%, 53%, and 98%, respectively. CONCLUSIONS: There was little differences among cTnI, cTnT, and CKMB after CABG to diagnose myocardial damage as assessed by new Q wave on the ECG. There was a trend of cTnI to be a better discriminator than cTnT, but it did not reach statistical significance.

Effect of trimetazidine on postischemic regional myocardial stunning in the halothane-anesthetized dog.

Trimetazidine (TMZ) has been described as a new antiischemic agent. Whereas its precise mechanism of action remains unknown, antioxidant properties and the ability to preserve high-energy phosphate metabolism have been reported. Accordingly, we studied whether TMZ may limit postischemic regional myocardial stunning (known to be caused by reactive oxygen species) and influence recruitment of contractile reserve by inotropic stimulation in a dog model, using halothane to maintain steady anesthesia throughout the experiment. Dogs were submitted to a 15-min coronary artery occlusion followed by reperfusion. The blinded protocol included a 3-day oral pretreatment (1 mg/kg/day), a bolus injection (0.5 mg/kg), followed by intravenous infusion (0.5 mg/h) initiated 15 min before coronary artery occlusion. Despite lower heart rate (HR) and significant reduction of lipid peroxidation in treated dogs, myocardial stunning and recruitment of contractile reserve by dobutamine infusion in the postischemic myocardium were not modified by TMZ. Adenine nucleotide pool in the postischemic myocardium was considerably reduced as compared with the nonischemic myocardium in both groups. Therefore, in halothane-anesthetized dogs, the antioxidant properties of TMZ were not sufficient to protect myocardium in terms of postischemic dysfunction after 15-min ischemia.

Cretan Mediterranean diet for prevention of coronary heart disease.

As a result of the Seven Countries Study, the Mediterranean diet has been popularized as a healthy diet. Nevertheless, it has not replaced the prudent diet commonly prescribed to coronary patients. Recently, we completed a secondary, randomized, prospective prevention trial in 605 patients recovering from myocardial infarction in which we compared an adaptation of the Cretan Mediterranean diet with the usual prescribed diet. After a mean follow-up period of 27 mo, recurrent myocardial infarction, all cardiovascular events, and cardiac and total death were significantly decreased by > 70% in the group consuming the Mediterranean diet. These protective effects were not related to serum concentrations of total, low-density-lipoprotein (LDL), or high-density-lipoprotein (HDL) cholesterol. In contrast, protective effects were related to changes observed in plasma fatty acids: an increase in n-3 fatty acids and oleic acid and a decrease in linoleic acid that resulted from higher intakes of linolenic and oleic acids, but lower intakes of saturated fatty acids and linoleic acid. In addition, higher plasma concentrations of antioxidant vitamins C and E were observed. We conclude that a Cretan Mediterranean diet adapted to a Western population protected against coronary heart disease much more efficiently than did the prudent diet. Thus, it appears that the favorable life expectancy of the Cretans could be largely due to their diet.

Lack of successful reanimation of pig hearts harvested more than 10 minutes after death.

BACKGROUND: The aim of this study was to evaluate the viability of arrested pig hearts harvested after animal death. METHODS: Hearts (n = 25) were preserved for 2 hours by cold storage (4 degrees C) with St. Thomas' cardioplegic solution no warm ischemia (0 minutes; control) or 10, 20, 30, or 60 minutes of in situ warm ischemia (animal exsanguination). Hearts were then reperfused for 1 hour with whole blood with an in vitro functional testing system. Left ventricular developed pressure and coronary flow were measured during reperfusion. Energetic compound measurements and histologic analysis were performed on tissue biopsy specimens. RESULTS: After 10- and 20-minute warm ischemia, hearts showed a significant decrease in energetic compounds, a 51% and 73% decreases of left ventricular developed pressure, and 38% and 65% decreases in coronary flow, respectively. After 30 minutes hearts showed irreversible ischemic injury with ultrastructural tissue damage, a large decrease in energetic adenine nucleotide compounds, and an inability to beat more than 15 minutes after reperfusion. CONCLUSION: We conclude that in contrast with other species, pig hearts harvested 10 minutes or more after animal exsanguination fail to be successfully reanimated.

Antegrade/retrograde cardioplegia in arterial bypass grafting: metabolic randomized clinical trial.

The metabolic effects of combined antegrade/retrograde and antegrade cardioplegia on myocardial protection were evaluated and compared in 30 patients who underwent myocardial revascularization. All patients had three-vessel coronary artery disease, and the revascularization was done with exclusive use of arterial grafts (internal mammary artery, gastroepiploic artery). Myocardial protection consisted of oxygenated crystalloid cardioplegia, topical slushed ice, and moderate systemic hypothermia (34 degrees C). The patients were randomly separated into two groups: group A (n = 15), who received antegrade cardioplegia, and group A/R (n = 15), who received combined antegrade/retrograde cardioplegia. There was no significant difference between the two groups concerning preoperative and intraoperative data. After the first dose of cardioplegia, right ventricular temperature was significantly lower in group A/R (15 +/- 2 degrees versus 19 +/- 5 degrees C; p < 0.05), and there was no significant difference between the two groups in left ventricular temperature. Coronary sinus blood samples were obtained before bypass and 5, 10, and 15 minutes after reperfusion; there was no difference between the two groups concerning lactates, superoxide dismutase, and glutathione peroxidase. After reperfusion, malondialdehyde levels increased significantly in group A and there was no change in group A/R, with a significant difference between the two groups (at 10 minutes after reperfusion, 0.80 +/- 0.20 versus 0.53 +/- 0.16 mumol/L; p < 0.05). Right and left ventricular myocardial biopsies were performed before bypass and 15 minutes after reperfusion; there was no significant difference between the two groups concerning adenosine triphosphate and creatine phosphate myocardial concentrations.(ABSTRACT TRUNCATED AT 250 WORDS)

The beneficial effect of dietary antioxidant supplementation on platelet aggregation and cyclosporine treatment in heart transplant recipients.

To determine whether dietary antioxidant supplementation can reduce platelet reactivity in heart transplant recipients, 20 patients were prospectively randomized to receive either 500 IU vitamin E orally per day in the form of acetate for 2 months or no vitamin E. Blood creatinine (P = 0.01) and lymphocyte count (P = 0.009) significantly decreased only in supplemented patients, whereas the cyclosporine blood level was not modified. Platelet aggregation was stable in control patients but significantly decreased in supplemented patients in response to either thrombin (from 8.3 +/- 0.9% of maximum aggregation to 3.7 +/- 0.7, P = 0.001) or ADP (secondary wave: from 44.7 +/- 5.9% to 33.2 +/- 7.0, P = 0.02). Thus antioxidant supplementation tended to improve immunosuppression (by reducing lymphocyte count), to reduce cyclosporine nephrotoxicity, and to decrease the high thrombotic risk associated with heart transplantation.

Mediterranean alpha-linolenic acid-rich diet in secondary prevention of coronary heart disease.

In a prospective, randomised single-blinded secondary prevention trial we compared the effect of a Mediterranean alpha-linolenic acid-rich diet to the usual post-infarct prudent diet. After a first myocardial infarction, patients were randomly assigned to the experimental (n = 302) or control group (n = 303). Patients were seen again 8 weeks after randomisation, and each year for 5 years. The experimental group consumed significantly less lipids, saturated fat, cholesterol, and linoleic acid but more oleic and alpha-linolenic acids confirmed by measurements in plasma. Serum lipids, blood pressure, and body mass index remained similar in the 2 groups. In the experimental group, plasma levels of albumin, vitamin E, and vitamin C were increased, and granulocyte count decreased. After a mean follow up of 27 months, there were 16 cardiac deaths in the control and 3 in the experimental group; 17 non-fatal myocardial infarction in the control and 5 in the experimental groups: a risk ratio for these two main endpoints combined of 0.27 (95% CI 0.12-0.59, p = 0.001) after adjustment for prognostic variables. Overall mortality was 20 in the control, 8 in the experimental group, an adjusted risk ratio of 0.30 (95% CI 0.11-0.82, p = 0.02). An alpha-linolenic acid-rich Mediterranean diet seems to be more efficient than presently used diets in the secondary prevention of coronary events and death.

Platelet aggregation and HDL cholesterol are predictive of acute coronary events in heart transplant recipients.

BACKGROUND: Sudden death (SD) and acute myocardial infarction (AMI) are the main complications limiting long-term survival after heart transplantation (HT). They are unpredictable and, at present, unpreventable. Platelet aggregation (PA) has recently emerged as a significant prognostic indicator in nontransplanted coronary disease patients. The main purpose of the present study was to evaluate to what extent PA could predict SD and AMI in long-term survivors of HT independently of serum lipid levels. METHODS AND RESULTS: We studied 207 patients. All received triple immunosuppressive therapy. During follow-up, the incidence of SD and AMI was determined, and the independent role of PA as predictor was evaluated with other usual risk factors by a Cox multivariate regression model. There were 11 SDs and 14 AMIs after an average follow-up of 642 days, giving an average incidence rate of 7.3 events per year per hundred patients. By univariate analysis, the most potent predictors were ADP-induced platelet aggregation (positive association) and total cholesterol (negative association). Age and length of time since transplant were not predictors. By multivariate analysis, only the secondary wave of ADP-induced platelet aggregation (P = .001) and high-density lipoprotein cholesterol (P = .03) were independent predictors. The relative risk of SD or AMI based on a comparison between patients with high (> 36%) or low (< 36%) ADP-induced platelet aggregation was 4.3 (95% confidence interval, 1.9 to 9.5, P = .0001). CONCLUSIONS: This study provides the first demonstration of an association between increased platelet aggregation and subsequent SD or AMI in HT recipients. It suggests that platelets and thrombosis also are implicated in the pathogenesis of AMI and SD in HT recipients. Identification of a safe and effective antiplatelet therapy should be actively pursued.

Increased production of reactive oxygen species in pharmacologically-immunosuppressed patients.

HIV-infected patients and transplanted patients share similar immunosuppressed status. Recent insights gained through the field of heart transplantation may help to clarify the role of reactive oxygen species in HIV-infected patients.

Comparison of different techniques of hypothermic pig heart preservation.

The aim of this study was to compare several methods of hypothermic heart preservation. Isolated pig hearts were preserved for 24 hours in cold cardioplegic solution (St. Thomas' Hospital modified solution) by continuous perfusion (group I), microperfusion (group II), or simple storage (group III). The findings were then compared with those from hearts harvested and immediately reperfused (the control group). Group III hearts showed lower adenosine triphosphate preservation (0.47 +/- 0.18 mumol/g) than did group I and II hearts and the control hearts (1.86 +/- 0.40, 1.98 +/- 0.27, and 1.84 +/- 0.55 mumol/kg, respectively). Electronic microscopy studies also revealed that the myocardial cells in the group III hearts appeared to be damaged. After the hearts had undergone preservation, myocardial function was studied for 60 minutes under nonworking conditions using an ex vivo functional testing system. For group III, the mean left ventricular developed pressure and ventricular compliance (16 +/- 22 and 63 +/- 48 mm Hg, respectively) differed significantly from those for group I (83 +/- 26 and 0 +/- 0 mm Hg, respectively), group II (83 +/- 33 and 14 +/- 18 mm Hg, respectively), and the control group (115 +/- 13 and 0 +/- 0 mm Hg, respectively). We concluded from our findings that perfusion methods are superior to cold storage but inadequate to maintain heart viability for the long term during hypothermia. These techniques must be improved before they can be adopted for clinical use.

[Value of C-reactive protein determination in small cell lung cancer]. / Intérêt du dosage de la protéine C-réactive dans le cancer bronchique à petites cellules.

A prospective analysis of serum levels of C-reactive protein (CRP) has been conducted on a series of 39 small cell lung cancer (SCLC) patients during the first course of chemotherapy in order to evaluate the predictive value of this marker on tumoral extension at diagnosis and response to therapy. Serum levels of CRP were measured before chemotherapy (day 0) and during the first two days of treatment (day 1, day 2). Twenty-three of 32 evaluable patients (71%) had extensive disease. The mean pre-treatment CRP level was significantly higher in this group than in the group of patients with limited disease (52.3 mg/l vs 15.8 mg/l, P = 0.02). Twenty-three patients responded to treatment and nine did not. The evolution of serum CRP levels in both groups was compared between day 0 and day 2. A more than two-fold increase of initial CRP levels showed a 100% predictive value for response. On the other hand, a decrease by more than 50% of initial serum levels was associated with a negative predictive value of 75% for response. We conclude that the follow-up of CRP levels during initial chemotherapy of SCLC might be useful in the initial evaluation of tumoral extension and in the early prediction of response to therapy.

Acute myocardial infarction in dogs with experimental diabetes.

OBJECTIVE: The aim was to examine whether diabetes interferes with the development of myocardial injury in a canine ischaemia-reperfusion model. METHODS: Non-insulin-requiring diabetes was induced in dogs by the streptozotocin-alloxan method. After 75 d, the dogs were anaesthetised and myocardial infarction was provoked by occluding the left anterior descending coronary artery for 2 h followed by 6 h reperfusion. RESULTS: Diabetic dogs had higher blood glucose [9.4(SEM 1) mmol.litre-1], fructosamine [417(57) mumol.litre-1], and glycated haemoglobin [3.3(0.7)%], than control dogs [5.5(0.6), p = 0.04, 243(15), p = 0.01, and 0.7(0.2), p = 0.003, respectively], and they also had higher serum lipids (p = 0.001) and platelet aggregation (p = 0.03). Area at risk was similar in diabetic and control dogs but in contrast to controls (r = 0.78, p = 0.007), area at risk and infarct size were not correlated in diabetics (r = 0.08). In both groups, collateral flow was the major determinant of infarct size: r = -0.73 in controls (p = 0.02) and -0.97 in diabetics (p = 0.001). In spite of higher subendocardial collateral flow in diabetics [representing 21.6(6)% of the flow in the corresponding non-ischaemic zone] than in controls [11.2(6)%], infarct size was similar in both groups. However, the mean observed infarct size in the diabetic group [7.5(2.8)% of the left ventricle] was significantly (p < 0.03) larger than the mean predicted infarct size [5.2(2)%]. Multivariate analysis confirmed that diabetes, as well as collateral flow, is an independent (p = 0.03) predictor of infarct size. CONCLUSIONS: For a given collateral flow, diabetic dogs develop larger infarcts than controls. Further studies are required to investigate the biochemical mechanism(s) underlying this deleterious effect. However, this may partly explain the poor prognosis of myocardial infarction in diabetic persons.

Quantitative reduction of MTT by hearts biopsies in vitro is an index of viability.

The aim of this study is to evaluate the use of tetrazolium reductase (TR) activity as an indicator of myocardial viability in an isolated arrested pig heart biopsy model. Methyl Tetrazolium (MTT) is cleaved by an enzyme in the presence of coenzymes NAD, NADP. Cleavage yields a highly colored formazan product which is DMSO soluble. Efficient bioreduction of MTT has been investigated with heart biopsies. The relationship between MTT reduction and (1) oxygen consumption (r = 0.96, P < 0.001), (2) the sum of the adenine nucleotide levels (r = 0.87, P < 0.001) and (3) localization of coloration, has been established. The use of MTT in colorimetric assays offers high sensitivity. MTT reduction is a valid method. It is rapid and reproducible, and can be used as an indicator of myocardial viability. The MTT test has been used to rapidly compare the effect of different cardioplegic solutions (St Thomas and improved St Thomas) on hypothermic cardiac preservation. Significant differences have been established between the two solutions (P < 0.01).

Dacron vascular biomaterial triggers macrophage ectoenzyme activity without change in cell membrane fluidity.

Biomaterials induce an inflammatory reaction characterized by a rapid recruitment at the implantation site of polymorphonuclear cells and macrophages. In the course of the inflammatory response, the cellular activation triggers expression of a number of enzymes, such as 5'-nucleotidase, which is widely distributed in animal cell membranes as an ectoenzyme. It is now well established that 5'-nucleotidase activity decreases following the contact of inflammatory cells with foreign particles. In this paper we investigate a possible correlation between the enzymatic activities and the dynamic properties of the cell membrane bilayer. Dacron pieces were introduced into rats' peritoneal cavities for a period of 6 h, after which the peritoneal cells were harvested, and various enzyme assays performed, including those for cytoplasmic, lysosomal, and ectoenzymes. In parallel, we studied cell membrane fluidity, using fluorescence polarization of 1-(4-trimethylammoniumphenyl)-6-phenyl-1,3,5-hexatriene (TMA-DPH), and cellular ultrastructural alteration resulting from the cell-biomaterial interactions using scanning and transmission electron microscopy. Our results show that: 1) macrophages spread around the Dacron fibers with cytoplasmic finger-like projections, but no phagolysosomes, 2) 5'-nucleotidase levels decrease with surgical trauma in comparison with the resident cell exudate, 3) implantation of biomaterials slightly modify the 5'-nucleotidase levels observed in the sham animal, 4) no differences in the anisotropy values indicating that membrane lipid order within the cells could not account for the observed decrease of 5'-nucleotidase activity. Thus, we can suggest that 5'-nucleotidase expression may reflect a particular feature of cell activation without a phagocytic process.

Comparison of continuous microperfusion and cold storage for pig heart preservation.

The aim of this study was to compare two methods of hypothermic heart preservation. Isolated hearts of pigs were preserved in cold cardioplegic solution (St. Thomas Hospital solution) either by simple storage or continuous microperfusion (with a new perfusion device) for 6 hours (group I, n = 12), 12 hours (group II, n = 12) and 24 hours (group III, n = 12). After storage, the myocardial function was studied for 60 minutes under nonworking conditions with an ex vivo functional testing system. Hearts preserved 24 hours by cold storage (group III) showed ventricular compliance and mean spontaneous left ventricular developed pressure significantly lower than hearts preserved by microperfusion (respectively, 63 +/- 47 versus 14 +/- 18 mm Hg and 16.8 +/- 22.0 versus 83 +/- 33 mm Hg). After 12 hours (group II) of preservation, mean left ventricular developed pressure was higher in microperfused hearts compared to immersed hearts (respectively, 133.3 +/- 39.0 versus 83.1 +/- 27.0 mm Hg, p < 0.05), whereas after 6 hours of preservation, no functional difference was observed between the microperfused and the immersed hearts. Hearts were also studied using myocardial biopsy specimens taken at the end of the preservation. The biopsy specimens were analyzed for high-energy phosphates. After 6 hours of preservation, the microperfusion group showed higher levels of adenosine triphosphate and total adenine nucleotides (adenosine triphosphate + adenosine diphosphate + adenosine monophosphate) (respectively, 4.60 +/- 0.5 mumol/gm and 5.98 +/- 0.5 mumol/gm fresh tissue) versus the cold storage group (respectively, 3.10 +/- 0.4 mumol/gm and 3.75 +/- 0.4 mumol/gm).(ABSTRACT TRUNCATED AT 250 WORDS)

Lipid peroxides and antioxidant defenses in accelerated transplantation-associated coronary arteriosclerosis.

Accelerated coronary artery disease develops in most if not all heart transplant recipients within the first year after transplantation. Increased lipid peroxidation seems to be involved in atherogenesis. In these patients we have investigated whether there is an association between lipid peroxidation, reduced antioxidant defenses, and some conventional coronary risk factors. Lipid peroxides, lipids, uric acid, albumin, antioxidant enzymes and their cofactors (the trace elements selenium, iron, copper, and zinc) have been determined in heart transplant recipients compared with nonrecipients with coronary artery disease. Lipid peroxides (p = 0.002) and uric acid (p = 0.01) were higher and zinc (p = 0.001) was lower in heart transplant recipients. Thirteen of 30 transplant recipients compared with one of 30 nonrecipients (p < 0.001) had very low (less than 10 mumol/L) zinc levels. Antioxidant enzymes and other trace elements were not significantly different. In univariate regression analysis, zinc correlated positively with albumin (p = 0.02) and negatively with lipid peroxides (p < 0.05). Uricemia had a strongly positive correlation with hydroperoxides (r = 0.45; p = 0.0001). In stepwise multivariate regression analysis, lipids, uricemia, creatinine, and zinc were significant (p < or = 0.004) predictors of the lipid peroxide level. Cyclosporine and corticosteroid dosages were significant (p = 0.01) determinants of zinc concentration in the transplant recipients. Although a causal relationship between increased lipid peroxidation and accelerated arteriosclerosis is not definitely demonstrated, the results of this analysis suggest new insights into conventional coronary disease risk factors and possible therapeutic interventions; further controlled trials are needed.