Serum complement activation in congestive heart failure.

BACKGROUND: Although activation of the complement system in myocardial infarction and cardiopulmonary bypass has been shown to contribute to myocardial injury, its role in congestive heart failure (CHF) is unknown. The purpose of this study was to determine the presence of terminal complement activation and its relation to clinical outcomes in patients with CHF. METHODS: We measured serum levels of the terminal complement complex C5b-9 in 36 patients with symptomatic heart failure and left ventricular ejection fraction <40%. We compared the serum C5b-9 levels of these patients with CHF with a group of 12 age-matched control patients. Combined clinical outcomes (death, urgent heart transplantation, or hospitalization with worsening heart failure) at 6 months were determined. RESULTS: The serum C5b-9 [median (25th to 75th percentiles)] levels in 36 patients with CHF [101.5 ng/mL (40 to 164)] were significantly (P =.003) higher than in the 12 control patients [36.5 ng/mL (22 to 50)]. Significantly more of the patients with CHF with the highest levels of C5b-9 (highest 50th percentile) had New York Heart Association class IV symptoms (67% vs 33%; P =.04) and adverse clinical outcomes by 6 months (56% vs 17%; P =.02) compared with the patients with CHF with lower levels (lowest 50th percentile). CONCLUSIONS: We have described a significant elevation in circulating C5b-9, the terminal complement complex, in patients with symptomatic heart failure and have observed an association between high levels of C5b-9 and near-term adverse events.

Modulation of circulating cellular adhesion molecules in postmenopausal women with coronary artery disease.

OBJECTIVES: The present study examined the association of estrogen (E2) and the inflammatory response of endothelium in coronary artery disease (CAD) by measuring circulating cellular adhesion molecules (cCAMs) in subjects with atherosclerosis. BACKGROUND: Atherosclerotic plaque demonstrates features similar to inflammation. Endothelial cell activation by inflammatory cytokines induces expression of cellular adhesion molecules (CAMs), thereby perhaps augmenting leukocyte adhesion and recruitment and subsequent development of atherosclerosis. The incidence of CAD is lower in women; this may be due to the cardioprotective effects of E2. METHODS: Consecutive eligible subjects with CAD admitted for cardiac catheterization were studied. The groups evaluated were men, postmenopausal women receiving E2 replacement therapy (ERT), postmenopausal women not receiving ERT and premenopausal women. Control groups included men and women without CAD. Preprocedural blood samples were drawn from all groups. Measurements of cCAMs, E-selectin, vascular cell adhesion molecule-1 (VCAM-1) and intercellular adhesion molecule-1 were performed by enzyme-linked immunoabsorbant assay. E2 levels were assessed by radioimmunoassay. RESULTS: We observed a statistically significant increase in all cCAMs in men with CAD and postmenopausal women with CAD not receiving ERT compared with postmenopausal women with CAD receiving ERT. Premenopausal women with CAD and postmenopausal women with CAD receiving ERT had a significant increase in VCAM-1 alone compared with the female control group. CONCLUSIONS: A possible mechanism by which E2 exerts one of its cardioprotective effects is by limiting the inflammatory response to injury by modulating the expression of CAMs from the endothelium.

Acute cocaine effects on absolute cerebral blood flow.

Cocaine use has been associated with vasoconstriction and stroke, and several studies have demonstrated that it decreases relative cerebral blood flow (rCBF) in humans. However, rCBF has not been quantitated. We compared 40 mg IV cocaine hydrochloride to placebo effects on absolute rCBF in four cocaine users using 99mTc-HMPAO SPECT with a modified microsphere model for CBF quantitation. Cocaine produced significant decreases in rCBF in all regions studied with a mean decrease of 30% in absolute whole brain blood flow (P = 0.002) which was 3-fold greater than relative blood flow changes.

IL-8 and angiogenesis: evidence that human endothelial cells lack receptors and do not respond to IL-8 in vitro.

It has been established that IL-8 triggers angiogenesis in vivo, but this effect may be mediated either by IL-8-recruited leukocytes or by direct actions of IL-8 upon endothelial cells (EC). We have approached this question by examining interactions of recombinant human IL-8 with cultured large vessel and microvascular human EC. We are unable to detect specific IL-8 binding to cultured human umbilical vein endothelial cells (HUVEC) or leukocyte-like IL-8 receptor mRNA expression by either cultured HUVEC or human dermal microvascular endothelial cells (DMEC). We find no alteration of cytoplasmic calcium concentration ([Ca2+]i) in either cell type in response to IL-8 treatment. Finally, we find no IL-8-induced change in EC proliferative rates in the presence or absence of endothelial cell growth factor. Our data favour an indirect action for IL-8 as an angiogenic factor.

Effect of injectate temperature and thermistor position on reproducibility of thermodilution cardiac output determinations.

STUDY OBJECTIVE: The purpose of this study was to evaluate the effect of thermistor position with varying injectate temperatures on the reproducibility of thermodilution cardiac output determination. The key hypothesis to be tested was that the positioning of the proximal thermistor at the right atrial port would improve the reproducibility of thermodilution cardiac output determination, independent of injectate temperature. DESIGN: Prospective randomized trial. SETTING: The study was performed in the cardiac catheterization laboratory of the West Haven Veterans Affairs Medical Center. PARTICIPANTS: Twenty consecutive patients undergoing right and left heart catheterizations were enrolled in the study. INTERVENTIONS: Each patient underwent triplicate determination of thermodilution cardiac output measurements under four experimental conditions: (1) ambient or room temperature injectate using an external thermistor in the injectate reservoir; (2) iced injectate using an external thermistor; (3) room temperature injectate using an internal right atrium (RA) thermistor; and (4) iced injectate using an RA thermistor. Reproducibility was assessed by the coefficient of variation (CV) and standard error of the mean percent (SEM%), of the triplicate measurements. MEASUREMENTS AND RESULTS: Using an internal RA thermistor improved the reproducibility of cardiac output determinations independent of injectate temperature. Using room temperature injectate, the CV was 12.8 percent using an external thermistor and 7.9 percent using an internal RA thermistor (p < 0.05). Using iced injectate, the CV was 10.2 percent using an external thermistor and 5.5 percent using an internal RA thermistor (p < 0.05). CONCLUSIONS: Reproducibility of thermodilution cardiac output determinations is improved when injectate temperature is measured internally, at the RA, as opposed to externally in the reservoir. This has clinical implications for determining significant changes in serial cardiac output determinations.