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Biomedical subjects

Michael Heesen

Publications and source records attributed to Michael Heesen.

14 recordsLinked to original sources
PubMed2006

Dobutamine does not influence inflammatory pathways during human endotoxemia.

OBJECTIVE: Catecholamines have anti-inflammatory and anticoagulant properties. Dobutamine is a synthetic catecholamine frequently used in patients with septic myocardial dysfunction. The objective was to determine whether a continuous infusion of dobutamine exerts immunomodulatory effects in healthy volunteers challenged with endotoxin. DESIGN: Prospective, open-label study. SETTING: Clinical research unit of a university hospital. PARTICIPANTS: Sixteen male healthy volunteers. INTERVENTIONS: Volunteers received a constant infusion with dobutamine (10 microg.kg.min, n = 8) or physiologic saline (n = 8). All participants were challenged with a bolus injection of endotoxin prepared from Escherichia coli (4 ng/kg). Dobutamine infusion was commenced 1 hr before endotoxin challenge and was continued until 3 hrs thereafter. MEASUREMENTS AND MAIN RESULTS: Dobutamine infusion was associated with an increase in mean arterial blood pressure (peak 122 +/- 5 mm Hg) and heart rate (peak 84 +/- 4 beats/min, both p < .05 vs. saline). Endotoxin injection induced the systemic release of cytokines (tumor necrosis factor-alpha, interleukins-6, -8, and -10) and secretory phospholipase A2, endothelial cell activation (increase in the plasma levels of soluble E-selectin and von Willebrand factor), activation of coagulation (increased plasma levels of soluble tissue factor, F1 + 2 prothrombin fragment, and thrombin-antithrombin complexes), and activation with subsequent inhibition of fibrinolysis (increased plasma concentrations of tissue-type plasminogen activator, plasminogen activator inhibitor type I, and plasmin-alpha2-antiplasmin complexes). None of these responses were influenced by dobutamine. CONCLUSIONS: Dobutamine, infused in a clinically relevant dose, does not influence inflammatory and coagulant pathways during human endotoxemia.

Adult↗
PubMed2006

Human endotoxemia induces down-regulation of monocyte CC chemokine receptor 2.

Upon injection of Escherichia coli lipopolysaccharide into human volunteers, the monocyte density of CC chemokine receptor 2 (CCR2) decreased. Minimal CCR2 density was observed 4 h after injection. Peak plasma concentrations of the CCR2 ligand monocyte chemotactic protein 1 and of tumor necrosis factor alpha were reached after 4 h and 2 h, respectively.

Adolescent↗
PubMed2005

MnSOD polymorphisms in sensitized patients with delayed-type hypersensitivity reactions to the chemical allergen para-phenylene diamine: a case-control study.

Dyes such as para-phenylene diamine (PPD) or related para-compounds are very common contact sensitizers in man. The corresponding contact dermatitis in sensitized individuals is a complex and common illness associated with considerable morbidity and social cost. It has been found that oxidative stress from reactive oxygen species (ROS) may play an important role in the pre-immunological phase of allergic contact dermatitis to PPD. Manganese superoxide dismutase (MnSOD) is one of the primary enzymes that directly scavenge potential harmful oxidizing species. A valine (Val) to alanine (Ala) substitution at amino acid -9, occurring in the MnSOD gene, has been associated with various disease risk. The aim of our study was to investigate possible associations of the MnSOD 47 T>C genotype in exon 2 (Ala-9Val) and the 339 T>C genotype in exon 3 (Ile58Thr) with contact sensitization to PPD in humans in a case-control study. The study was performed in 157 unrelated cases and 201 age- and gender-matched controls. The MnSOD genotypes were determined using LightCycler allele discrimination assays. No heterozygous (CT) or homozygous carriers (TT) for the Ile58Thr polymorphism were found. The frequency for the C allele of the Ala-9Val polymorphism was 51% (79/157) in cases and 49% (107/201) in controls. Homozygous CC carriers (Ala/Ala) were 27% (43/157) in cases and 23% (46/201) in controls (odds ratio [OR], 1.3; 95% confidence interval [CI], 0.8-2.1). Stratification into subgroups based on gender and age limited the association to females. Increased risk among homozygous CC carriers (Ala/Ala) was only found in the group of older females (over 45 years, 25% versus 18%; OR, 1.5; 95% CI, 0.7-2.34). These data suggest that the C (Ala) allele of MnSOD modifies contact dermatitis risk among older females, but is not an independent susceptibility factor for contact sensitization to PPD.

Adolescent↗
PubMed2003

Rapid and reliable genotyping for the Toll-like receptor 4 A896G polymorphism using fluorescence-labeled hybridization probes in a real-time polymerase chain reaction assay.

BACKGROUND: The Toll-like receptor 4 (TLR4) is involved in immune response to endotoxin as well as the pathogenesis of atherosclerosis. The TLR4 gene was shown to carry a single-nucleotide polymorphism (A896G). We developed a rapid-cycle polymerase chain reaction (PCR) which allows for rapid genotyping and, therefore, may be useful in clinical risk assessment. METHODS: Fluorescently labeled oligonucleotide hybridization probes were designed for the LightCycler instrument. A PCR product was generated in a single reaction followed by melting point analysis. Ninety-three German Caucasians were genotyped. The interleukin-1beta (IL-1beta) response to endotoxin was assessed after whole blood stimulation with endotoxin according to TLR4 genotypes. RESULTS: The method suggested by us is a time-saving technique requiring no additional manual steps. Frequencies of the A and G allele were 0.95 and 0.05, respectively. The study population was in Hardy-Weinberg equilibrium. The specificity of the method was confirmed by sequencing. The IL-1beta levels were lower in carriers of the G allele. CONCLUSIONS: This PCR assay is a rapid and reliable technique for TLR4 genotyping.

Genotype↗
PubMed2003

Cytokine response to endotoxin in individuals heterozygous for the Delta32 mutation of chemokine receptor CCR5.

Studies of mice with a targeted disruption of the CCR5 gene suggest that the CC chemokine receptor 5 (CCR5) is a determinant of the cytokine response to endotoxin. In humans, a naturally occurring mutation of the CCR5 gene is a 32-basepair (bp) deletion which precludes the translation of the gene into a functional transmembrane protein. To evaluate the cytokine phenotype of heterozygosity for the 32 deletion, we studied the endotoxin-stimulated release of tumor necrosis factor-alpha, Interleukin (IL)-6, IL-8, IL-10, and IL-12 in whole blood ex-vivo of healthy volunteers and patients undergoing elective cardiac bypass surgery. This operation represents a major surgical trauma associated with ischemia-reperfusion-injury and triggers a profound inflammatory response. In these patients, cytokine plasma concentrations were measured during and after cardiac surgery. No difference was found between the frequencies of the observed and expected CCR5 genotypes in the groups of individuals studied. Furthermore, no significant difference in ex-vivo or peri- and postoperative cytokine plasma concentrations was detected between CCR5 wild-type homozygotes and individuals carrying one defective CCR5 allele. Our results indicate that heterozygosity for the 32bp deletion of CCR5 is not associated with an altered cytokine response to endotoxin or to a major surgical trauma when compared with individuals homozygous for the wild-type allele.

Adult↗
PubMed2003

Incidence of pain after intravenous injection of a medium-/long-chain triglyceride emulsion of propofol. An observational study in 1375 patients.

BACKGROUND AND OBJECTIVE: To assess incidence and intensity of pain on intravenous injection of propofol (CAS 2078-548) in an emulsion of medium-chain/long-chain triglycerides (MCT/LCT, 50:50) in patients undergoing different elective surgical interventions. METHODS: The new solvent was used for induction of general anesthesia. Spontaneous pain reactions and pain elicited upon questioning were assessed. Patients were asked to grade the pain as mild, moderate or severe. Co-medication with sedative or analgesic drugs, size of the intravenous cannulae, site of injection and administration as a single bolus or in divided doses were recorded. RESULTS: Overall incidence of pain was 28.4% (390 out of 1375 patients). Twelve percent of the patients complained spontaneously and 16.4% reported pain after questioning. Pain intensity was graded as mild by 16.7% of the patients. The incidence of pain was significantly less when using an antecubital vein compared with a forearm or dorsal hand vein (p = 0.017 spontaneously reported pain, p = 0.001 pain elicited upon questioning). The number of patients complaining spontaneously of pain was significantly lower (p = 0.006) for large size than for small and medium size cannulae. CONCLUSIONS: The incidence of pain on injection of a medium-/long-chain triglyceride propofol formulation was 28.4% with 16.7% of the patients reporting mild pain. The use of an antecubital vein or a large size venous cannula appears to reduce the injection pain.

Adult↗
PubMed2003

Linkage disequilibrium between tumor necrosis factor (TNF)-alpha-308 G/A promoter and TNF-beta NcoI polymorphisms: Association with TNF-alpha response of granulocytes to endotoxin stimulation.

OBJECTIVE: Controversial data have been reported on the association between the tumor necrosis factor (TNF)-alpha-308 G[U279C]A promoter polymorphism or the TNF-alpha I polymorphism with TNF-alpha plasma concentrations. The purpose of this study was to evaluate whether there is a linkage disequilibrium between the two polymorphisms. Moreover, the influence of these polymorphisms on the TNF-alpha synthesis of activated granulocytes was studied. DESIGN: Analysis of TNF-alpha concentrations of human whole blood after endotoxin stimulation. SETTING: Medical research laboratory. PATIENTS: Healthy human volunteers. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Healthy human volunteers were genotyped for both TNF polymorphisms by means of polymerase chain reaction. TNF-alpha plasma concentrations were determined with chemiluminescence after incubation of whole blood with endotoxin. A strong (p <.0001) linkage disequilibrium was found for the TNF-beta I and the TNF-alpha-308 genetic polymorphisms. Almost all individuals homozygous for the TNF-B2 allele of the TNF-beta I polymorphism were also TNF-alpha-308 G homozygotes. Carriers of the TNF-alpha-308 genotype AG had a significantly higher TNF-alpha production capacity than G homozygotes. The TNF-beta I genotype TNF-B1/TNF-B2 was associated with significantly higher TNF-alpha concentrations than the genotype TNF-B2/TNF-B2. Individuals homozygous for the TNF-B2 and the TNF-alpha-308 G alleles had a significantly reduced TNF-alpha response compared with individuals heterozygous for both TNF polymorphisms. CONCLUSIONS: A linkage disequilibrium between the two TNF polymorphisms was found. This study revealed a significant association between genotype and phenotype for both TNF polymorphisms. Heterozygosity for both TNF polymorphisms is associated with an increased TNF-alpha response.

Granulocytes↗
PubMed2002

The -260 C-->T promoter polymorphism of the lipopolysaccharide receptor CD14 and severe sepsis in trauma patients.

OBJECTIVE: CD14, expressed on the cell surface of monocytes and hepatic Kupffer cells, interacts with Gram-positive and Gram-negative bacteria. Upon CD14 stimulation, these cells respond with the enhanced release of cytokines involved in the pathophysiology of sepsis. The purpose of this study was to evaluate whether the genotype distribution of the -260 C-->T promoter polymorphism of the CD14 gene is associated with the development of severe sepsis in trauma patients. PATIENTS AND PARTICIPANTS: Fifty-eight severely injured blunt trauma patients with an injury severity score of 16 or more and without pre-existing chronic diseases. MEASUREMENTS AND RESULTS: Genotyping for the single nucleotide exchange polymorphism of the CD14 gene was performed by means of a real-time polymerase chain reaction with fluorescence-labeled hybridization probes. Diagnosis of severe sepsis was based on the criteria of the ACCP/SCCM criteria. Fourteen out of the 58 patients (24.6%) developed a trauma-related severe sepsis. The overall allele frequency was 0.58 for the C allele and 0.42 for the T allele. The genotype distribution (TT 0.19, CT 0.47 and CC 0.35) did not differ significantly from a previously reported control group of healthy blood donors. There was no significant difference of the genotype distribution or allele frequency between trauma patients with severe sepsis and patients with an uncomplicated clinical course. CONCLUSIONS: This pilot study suggests that the CD14 -260 polymorphism is not associated with an increased risk of severe sepsis in trauma patients.

Adult↗
PubMed2002

Can the interleukin-6 response to endotoxin be predicted? Studies of the influence of a promoter polymorphism of the interleukin-6 gene, gender, the density of the endotoxin receptor CD14, and inflammatory cytokines.

OBJECTIVES: To evaluate whether the -174 G/C promoter polymorphism of the interleukin-6 gene, gender, the monocyte density of the endotoxin receptor CD14, or the inflammatory cytokines tumor necrosis factor-alpha or interleukin-1beta influence the interleukin-6 response of whole blood to endotoxin. DESIGN: Analysis of interleukin-6 release from endotoxin-stimulated human whole blood. SETTING: Medical research laboratory. PATIENTS: Healthy human blood donors. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: The interleukin-6 -174 G/C and the tumor necrosis factor -308 G/A promoter polymorphisms were determined by real-time polymerase chain reaction assay by using specific fluorescence labeled hybridization probes. Monocyte CD14 expression was assessed by flow cytometry. After incubation of whole blood with endotoxin, plasma concentrations of interleukin-6, tumor necrosis factor-alpha, and interleukin-1beta were measured by means of chemiluminescence. The interleukin-6 concentrations were lower (p = .005) in individuals who were CG heterozygotes compared with individuals homozygous for the C or the G. The difference between C and G homozygotes was not significant (p = .67). The interleukin-6 response was enhanced in men compared with women (p = .015). There was no correlation between interleukin-6 concentrations and monocyte CD14 density. Interleukin-6 concentrations correlated with the concentrations of tumor necrosis factor-alpha (r = .59, p = .01) and interleukin-1beta (r = .47, p = .01). There was no linkage between the tumor necrosis factor -308 and the interleukin-6 -174 polymorphisms. CONCLUSIONS: The interleukin-6 response to endotoxin was influenced by gender and correlated with the concentrations of more proximal cytokine tumor necrosis factor-alpha and interleukin-1beta. The interleukin-6 -174 G/C promoter polymorphism can only partly predict the interleukin-6 response of human whole blood to endotoxin stimulation, and the results were different from previous reporter gene assays that reported higher interleukin-6 concentrations for the G allele. Tumor necrosis factor -308 G homozygotes produce the lowest tumor necrosis factor concentrations. The number of tumor necrosis factor -308 G homozygotes was not higher among interleukin-6 -174 heterozygotes, and thus this cannot account for their significantly smaller interleukin-6 production.

Adult↗
PubMed2002

Tumor necrosis factor gene polymorphisms, leukocyte function, and sepsis susceptibility in blunt trauma patients.

The tumor necrosis factor alpha (TNF-alpha) -308 G/A and TNF-beta NcO1 polymorphisms have been described to be associated with an increased risk for sepsis in critically ill patients. Functional consequences associated with these polymorphisms remain unclear. We compared the genotype distribution of these TNF polymorphisms with susceptibility to severe sepsis and leukocyte function in blunt trauma patients (n = 70; mean injury severity score, 24 points [range, 4 to 57). Severe sepsis was defined according to the American College of Chest Physicians-Society of Critical Care Medicine consensus conference criteria. Genotyping for the NcO1 polymorphism (alleles TNFB1 and TNFB2) was performed by PCR and digestion of the products with NcO1, and that for the TNF-alpha -308 G/A polymorphism (alleles TNF1 and TNF2) was performed by real-time PCR. Leukocyte function was assessed by measurement of the production of endotoxin-induced cytokines (TNF-alpha, interleukin-6 [IL-6], and IL-8) in whole blood. TNF-alpha, IL-6, and IL-8 were determined by enzyme-linked immunosorbent assay. For the genotypes of the TNF-alpha -308 G/A polymorphism, differences in the frequency of development of severe sepsis were not detectable. Patients developing severe sepsis after trauma were significantly more likely to possess a homozygous genotype of the TNF-beta NcO1 polymorphism. Compared with heterozygotes, the odds ratio for the TNFB2/B2 genotype for the development of severe posttraumatic sepsis was 11 (P = 0.01), and that for the TNFB1/B1 genotype was 13 (P = 0.014). TNF-alpha -308:TNF-beta NcO1 haplotype analysis showed that the TNFB2:TNF2 haplotype is significantly negatively associated with development of severe sepsis. Patients homozygous for the TNFB1 or TNFB2 allele showed a persistently higher cytokine-producing capacity during at least 4 to 8 days after trauma than the heterozygotes. In patients homozygous for the TNF1 allele, a higher TNF-alpha- and IL-8-producing capacity was found only at day 1 after trauma. Although the TNF-beta NcO1 polymorphism appears to be less likely to be causative for development of severe sepsis after trauma, it is thus far the only genetic marker identified which can be used as a relevant risk estimate for severe sepsis in trauma patients immediately after the injury.

Adult↗
PubMedDate not supplied

The interleukin-6 G(-174)C polymorphism and the ex vivo interleukin-6 response to endotoxin in severely injured blunt trauma patients.

The aim of this study was to evaluate whether the -174 G/C promoter polymorphism of the interleukin-6 (IL-6) gene is associated with the ex vivo, whole blood IL-6 response to endotoxin with the development of severe sepsis in severely injured, blunt trauma patients. Patients with a severe trauma and an injury severity score of 16 were included in the study. The IL-6 -174 G/C promoter polymorphism was determined by real-time polymerase chain reaction (PCR) assay using specific fluorescence-labelled hybridisation probes. Whole blood of the patients was stimulated with endotoxin and the IL-6 concentrations were measured by ELISA. There was no association between the IL-6 -174 genotypes and the ex vivo, stimulated IL-6 response: 25% of the patients developed severe sepsis later in the clinical course. These patients had higher IL-6 concentrations following whole blood stimulation on day 1 (p = 0.046) after the trauma than patients with uncomplicated post-traumatic recovery. The difference was even more significant on day 2 after the trauma (p = 0.02). High IL-6 responses in a whole blood stimulation assay with endotoxin on days 1 and 2 after a trauma are associated with severe post-traumatic sepsis. Genotyping for the IL-6 -174 G/C polymorphism does not allow early identification of trauma patients with a high, ex vivo IL-6 synthesis capacity.

Blood↗
PubMedDate not supplied

The CD14-260 C --> T promoter polymorphism co-segregates with the tumor necrosis factor-alpha (TNF-alpha)-308 G --> A polymorphism and is associated with the interleukin-1 beta (IL-1 beta) synthesis capacity of human leukocytes.

Genetic variations contribute to the interindividual variance in the cytokine response to endotoxin. The gene of tumor necrosis factor-alpha (TNF-alpha) carries a polymorphism at position -308 of the promoter, consisting of a G/A exchange. To further elucidate the inherited mechanisms influencing cytokine levels, healthy human blood donors were studied. Genotyping for the TNF-alpha -308 and the CD14 -260 C/T promoter polymorphisms was carried out by real-time polymerase chain reaction assay using specific fluorescence-labelled hybridisation probes. A human whole blood assay was used to study the leukocyte TNF-alpha and IL-1 beta synthesis capacity upon endotoxin stimulation. We found a linkage disequilibrium between the TNF-alpha -308 G/A and the CD14 -260 C/T polymorphisms (p = 0.043). The CD14 -260 polymorphism was associated with IL-1 beta levels (p = 0.033) and higher values were found in C homozygotes. No association was found between the CD14 -260 genotypes or the TNF-alpha -308 - CD14 -260 genotypes and the TNF-alpha response.

Base Sequence↗
PubMedDate not supplied

The cytokine synthesis by heterozygous carriers of the Toll-like receptor 4 Asp299Gly polymorphism does not differ from that of wild type homozygotes.

Previous studies have found that heterozygosity for the A896G mutation of the endotoxin receptor TLR4 confers susceptibility to Gram-negative infections and septic shock. To evaluate the underlying mechanisms, we studied the association of the TLR4 polymorphism with endotoxin-induced cytokine synthesis in human whole blood. Monocyte CD14 density and monocyte count were also determined. Healthy individuals were genotyped by means of a real-time polymerase chain reaction. Plasma concentrations of TNF-alpha, IL-6, and IL-8 were measured by chemiluminescence. No significant differences in cytokine synthesis were observed between heterozygous individuals and homozygous carriers of the wild type allele. Our study suggests that heterozygosity for this TLR4 mutation is not a major factor determining the cytokine response to endotoxin.

Amino Acid Substitution↗