Prevalence and Strain Characterization of Clostridioides (Clostridium) difficile in Representative Regions of Germany, Ghana, Tanzania and Indonesia - A Comparative Multi-Center Cross-Sectional Study

Clostridioides (Clostridium) difficile infections (CDI) are considered worldwide as emerging health threat. Uptake of C. difficile spores may result in asymptomatic carrier status or lead to CDI that could range from mild diarrhea, eventually developing into pseudomembranous colitis up to a toxic megacolon that often results in high mortality. Most epidemiological studies to date have been performed in middle- and high income countries. Beside others, the use of antibiotics and the composition of the microbiome have been identified as major risk factors for the development of CDI. We therefore postulate that prevalence rates of CDI and the distribution of C. difficile strains differ between geographical regions depending on the regional use of antibiotics and food habits. A total of 593 healthy control individuals and 608 patients suffering from diarrhea in communities in Germany, Ghana, Tanzania and Indonesia were selected for a comparative multi-center cross-sectional study. The study populations were screened for the presence of C. difficile in stool samples. Cultured C. difficile strains (n = 84) were further subtyped and characterized using PCR-ribotyping, determination of toxin production, and antibiotic susceptibility testing. Prevalence rates of C. difficile varied widely between the countries. Whereas high prevalence rates were observed in symptomatic patients living in Germany and Indonesia (24.0 and 14.7%), patients from Ghana and Tanzania showed low detection rates (4.5 and 6.4%). Differences were also obvious for ribotype distribution and toxin repertoires. Toxin A⁺/B⁺ ribotypes 001/072 and 078 predominated in Germany, whereas most strains isolated from Indonesian patients belonged to toxin A⁺/B⁺ ribotype SLO160 and toxin A^-/B⁺ ribotype 017. With 42.9–73.3%, non-toxigenic strains were most abundant in Africa, but were also found in Indonesia at a rate of 18.2%. All isolates were susceptible to vancomycin and metronidazole. Mirroring the antibiotic use, however, moxifloxacin resistance was absent in African C. difficile isolates but present in Indonesian (24.2%) and German ones (65.5%). This study showed that CDI is a global health threat with geographically different prevalence rates which might reflect distinct use of antibiotics. Significant differences for distributions of ribotypes, toxin production, and antibiotic susceptibilities were observed.

[Antibiotic Stewardship - From Bench to Bedside]

The article explains the practical implementation of Antibiotic Stewardship (ABS) in the clinic. With increasing prevalence of resistant bacteria, the medical profession is challenged to critically question and reduce antibiotic prescriptions. ABS programs are designed to support this. In particular, the involvement of clinic management in the ABS has to improve. There has to be a greater awareness of problems associated with antibiotic use and the data about it must be communicated transparently within the hospital. However, there is also a need for training in the medical profession. The pathophysiological understanding as well as the accurate diagnosis of infectious diseases must be improved. Doctors need courage to forego the use of antibiotics. The consensus within a department and a hospital for withholding antibiotics must be strengthened. However, the awareness of sepsis as an emergency needs to be raised as well, and it is important to focus on hygiene issues and not just on the rapid antibiotic therapy. Microbiological pre-analysis is of crucial importance. In this case, fewer swabs, but more meaningful analytical methods, such as blood cultures or invasive probes, must be attempted. Finally, interactions between clinicians, microbiologists and hospital hygienists are of great importance.

The Reduction in Antibiotic Use in Hospitals

BACKGROUND

Over 350 000 patients are treated in German hospitals for sepsis or pneumonia each year. The rate of antibiotic use in hospitals is high. The growing problem of drug resistance necessitates a reconsideration of antibiotic treatment strategies.

METHODS

Antibiotics were given liberally in the years 2010 and 2011 in a German 312-bed hospital. Special training, standardized algorithms to prevent unnecessary drug orders, and uniform recommendations were used in 2012 and 2013 to lessen antibiotic use. We retrospectively studied the hospital's mortality figures and microbiological findings to analyze how well these measures worked.

RESULTS

Antibiotic consumption fell from 67.1 to 51.0 defined daily doses (DDD) per 100 patient days (p <0.001) from the period 2010-2011 to the period 2012-2013. The mortality of patients with a main diagnosis of sepsis fell from 1% (95/305) to 19% (63/327; p = 0.001), while that of patients with a main diagnosis of pneumonia fell from 12% (22/178) to 6% (15/235; p = 0.038). The overall mortality fell from 3.0% (623/ 20 954) to 2.5% (576/22 719; p = 0.005). In patients with nosocomial urinary tract infections with Gram-negative pathogens (not necessarily exhibiting three- or fourfold drug resistance), the rate of resistance to three or four of the antibiotics tested fell from 11% to 5%.

CONCLUSION

Reducing in-hospital antibiotic use is an achievable goal and was associated in this study with lower mortality and less drug resistance. The findings of this single-center, retrospective study encourage a more limited and focused approach to the administration of antibiotics.

[Analgesia in intensive care medicine]

BACKGROUND

The administration of sedatives and analgesics on the intensive care unit (ICU) is routine daily practice. The correct discrimination between delirium, pain and anxiety or confusion is essential for the strategy and selection of medication. The correct pain therapy and sedation are essential for patient quality of life on the ICU and for the prognosis.

OBJECTIVE

The aim of this article is to present state of the art recommendations on the classification of pain and pain therapy on the ICU.

MATERIAL AND METHODS

An online search was carried out in PubMed for publications on the topics of "pain" and "ICU".

RESULTS

Critical care patients are frequently subjected to many procedures and situations which can cause pain. The perception of pain is, among other things, influenced by the degree of orientation, anxiety and the degree of sedation. The administration of analgesics and non-pharmacological approaches are effective in reducing the stress perceived by patients.

DISCUSSION

The main aim is improvement in the awareness of nursing and medical personnel for pain inducers and pain perception in ICU patients. The classification of pain must be made objectively. Therapeutic targets must be defined and in addition to the correct selection of pain medication, non-pharmacological approaches must also be consistently implemented.

Expected and observed mortality in critically ill patients receiving initial antibiotic therapy

OBJECTIVE

To evaluate the predictors of mortality in critically ill patients receiving initial antibiotic therapy (IAT; < 48 h after admission).

METHODS

Six hundred thirty-one consecutive patients admitted to an intermediate care (IMC) unit were included. IAT was initiated in 227 patients. Laboratory markers, interventions, medications, systemic inflammatory response syndrome (SIRS) and sepsis criteria, length of stay, and hospital mortality as well as expected mortality, based on the SAPSII-expanded score, were assessed retrospectively. Failure of IAT was defined as a rise in C-reactive protein (CRP) or leukocyte count on day 3 compared with the values on admission.

RESULTS

Patients with IAT were significantly older (67 ± 14 vs. 64 ± 14 years; p = 0.006) and had a higher prevalence of chronic renal failure (33 vs. 23 %; p = 0.015), chronic obstructive pulmonary disease (COPD; 27 vs. 16 %; p = 0.002), malignoma (17 vs. 9 %; p = 0.007), acute renal failure (11 vs. 4 %; p = 0.001), respiratory failure (22 vs. 7 %; p < 0.001), and a shock index < 1.0 (21 vs. 8 %; p < 0.001). Although patients with IAT did not have significantly different expected mortality compared with patients without IAT (19.2 vs. 14.5 %; p = 0.144), they did have a significantly higher observed mortality (16.7 vs. 3.7 %; p < 0.0001). Based on the number of SIRS criteria (0, 1, 2, or 3-4) or sepsis criteria (no sepsis, sepsis, or severe sepsis) fulfilled, expected mortality (16.4, 18.2, 20.6, or 21.0 %, respectively; p = 0.955/17.5, 18.3, or 23.4 %, respectively; p = 0.689) did not differ in IAT patients. In contrast, observed mortality differed significantly (4.8, 10.6, 20.6, or 29.4 %, respectively; p = 0.029/8.3, 19.7, or 29.3 %, respectively; p = 0.013). Patients who responded to IAT did not differ regarding comorbidities, SIRS or sepsis criteria, but they had a lower observed mortality (11.9 vs. 26.3 %; p = 0.008) than patients who failed to respond to IAT. Central venous lines were more frequently present in patients with failure to IAT when compared with those with response (51 vs. 22 %; p = 0.009). In the subgroup of patients with acute myocardial infarction (AMI), those with IAT (n = 41) were treated less frequently according to the current cardiac guidelines than those without (n = 124)

CONCLUSIONS

Patients with IAT have a high morbidity burden and higher observed than expected mortality. The SAPSII-expanded score does not seem to precisely estimate the risk of in-hospital mortality in these patients. Failure of response to IAT was associated with an even higher mortality. Whether central venous lines and nonadherence to cardiac care guidelines influence the mortality of patients with IAT should be investigated in further studies.

Chemical analyses and X-ray diffraction investigations of human hydroxyapatite minerals from aortic valve stenoses

A total of 23 solid, mineral-like samples from calcified aortic valves of human origin have been investigated by means of classic analytical techniques (atomic absorption spectroscopy) and powder X-ray diffraction methods (Rietveld approach). The calcification goes back to hexagonal Ca-deficient hydroxyapatite, and there is a large variance in absolute hydroxyapatite contents as well as in crystalline qualities. The source of the calcium deficiency has been traced back to the 4f calcium site of the crystal structure in P63/m, and the calcium loss is compensated by hydroxy group deficiencies. Despite no correlation between analytically and diffractionally determined calcium contents, the crystallinities of the samples and the sharpnesses of their Bragg peaks seem to be related with the sub-occupancy of the 4f calcium site.

Genetic variation at chromosome 1p13.3 affects sortilin mRNA expression, cellular LDL-uptake and serum LDL levels which translates to the risk of coronary artery disease

BACKGROUND

A single nucleotide polymorphism (SNP) rs599839 located at chromosome 1p13.3 has previously been associated with risk of coronary artery disease (CAD) and with serum levels of low-density lipoprotein cholesterol (LDL-C). A functional link explaining the association of SNP rs599839 with LDL-C levels and CAD risk has not yet been elucidated.

METHODS

We analyzed the association of rs599839 with LDL-C in 6605 individuals across a wide age spectrum and with CAD in four case-control studies comprising 4287 cases and 7572 controls. Genome-wide expression array data was used to assess the association of SNP rs599839 with gene expression at chromosome 1p13. Finally, we overexpressed sortilin in transfected cells to study LDL-uptake in vitro.

RESULTS

Each copy of the G-allele of rs599839 associated with a decrease of serum LDL-C by 0.14 mmol/L (90% confidence interval (CI) 0.09-0.17 mmol/L, p=2.6 x 10(-11)). Moreover, each copy of the G-allele associated with a 9% decrease of CAD risk (90% CI 4-14%) in the presently studied four case-control samples and with a 13% decrease (90% CI 10-17%, p=2.18 x 10(-9)) in a pooled meta-analysis including recent genome-wide association studies on CAD. The same allele was associated with higher mRNA-expression levels of the multiligand receptor sortilin (log transformed mRNA AA vs. GG=8.31 vs. 8.55; p=0.01). Overexpression of SORT1 cDNA resulted in a significant increase in LDL-particle uptake (+23%, p=0.01).

CONCLUSIONS

Rs599839 associates with decreased LDL-C and a lower risk of CAD. Effects appear to be mediated by increased sortilin expression and subsequently enhanced LDL-uptake into cells.

Parathyroid hormone gene variant and calcific aortic stenosis

BACKGROUND AND AIM OF THE STUDY

Calcific aortic stenosis (AS) is the most frequently acquired valvular disease of the elderly in the Western world. A genetic background for AS has been proposed. The deposition of calcium hydroxyapatite is the key problem of valve calcification; vitamin D and parathyroid hormone are major factors in calcium homeostasis. The vitamin D receptor (VDR) gene and parathyroid hormone (PTH) gene variants were selected as candidate genes.

METHODS

A total of 538 patients with severe calcific AS (identified echocardiographically) were characterized by left heart catheterization. A group of 536 patients in whom heart disease had been excluded by left heart catheterization served as a control population. The cardiovascular risk profile was assessed, and three gene variants were analyzed, namely VDR rs1544410, VDR rs1073810, and PTH rs6254.

RESULTS

Patients with AS were found to have a higher prevalence of the PTH AA genotype (108 +/- 20.1% versus 71 +/- 13.2%; p = 0.007), while the VDR gene revealed a marginal, but statistically non-significant, association. The age and risk profile was similar in both groups.

CONCLUSION

To date, the association of the PTH gene variant has been the only positive association studied in patients with AS in a large population. Hence, the polymorphism is within an intron; the molecular mechanisms of altered gene expression should undergo further investigation.

The 4G/5G promotor polymorphism of the plasminogen activator inhibitor-1 gene and late lumen loss after coronary stent placement in smoking and nonsmoking patients

BACKGROUND

Instent restenosis remains a significant clinical problem. Identification of patients at risk for instent restenosis may allow selection of individualized appropriate therapeutic approaches. Genetic polymorphisms have been suggested to be associated with the risk of instent restenosis. Smoking is known to influence hemostatic parameters.

HYPOTHESIS

This study investigated the influence of the 4G/5G promotor polymorphism of the plasminogen activator inhibitor type I (PAI-1) gene on instent restenosis in smoking and nonsmoking patients.

METHODS

In all, 300 consecutive patients (133 nonsmoking; 167 smoking) with elective coronary stent placement and 6-month angiographic follow-up were studied. Quantitative coronary angiography and genotyping with polymerase chain reaction analysis were performed in all patients.

RESULTS

Nonsmoking PAI-1 4G/4G carriers showed a significantly greater late lumen loss (n = 38; 0.54 +/- 0.53 mm) compared with nonsmoking PAI-1 4G/5G (n = 68; 0.38 +/- 0.45 mm) or 5G/5G (n = 27; 0.19 +/- 0.23 mm) carriers, analysis of variance (ANOVA) p < 0.001. Smoking patients with the genotypes 4G/4G (n = 46; 0.53 +/- 0.54 mm) and 4G/5G (n = 79; 0.37 +/- 0.41 mm) had a late loss similar to that of nonsmoking patients. Smoking 5G/5G carriers had the highest late loss of all smoking patients (n = 42; 0.63 +/- 0.50); ANOVA p < 0.05; nonsmoking 5G/5G vs. smoking 5G/5G p < 0.001.

CONCLUSION

The promotor polymorphism of the PAI-1 gene has a significant influence on instent restenosis after coronary stent implantation. The 5G/5G genotype predisposes nonsmoking gene carriers to less late lumen loss, whereas in smoking gene carriers this genotype is associated with the greatest late lumen loss. This might be explained by an altered expression pattern of hemostatic parameters.

Systemic and local levels of fetuin-A in calcific aortic valve stenosis

Calcific aortic valve stenosis, the most frequent heart valve disorder in developed countries, is an actively regulated process with similarities to bone formation. Fetuin-A has recently been identified as a potent circulating inhibitor of calcification. While several studies involving patients with end-stage renal disease have shown an association between low serum fetuin-A and cardiovascular calcification, nothing is known about fetuin-A serum levels in non-renal patients with calcific aortic valve stenosis. Furthermore, while fetuin-A has been localized in calcified areas of atherosclerotic arteries, data about fetuin-A deposition in stenotic aortic valves are unavailable at present. Serum fetuin-A levels were determined in patients with (n=31) and without (n=28) calcified aortic valve stenosis by ELISA. Creatinine and CRP levels were determined and glomerular filtration rate (GFR) was calculated by the MDRD formula. Immunohistochemistry for fetuin-A was performed on human calcified stenotic (n=14) and control (n=8) aortic valves using a monoclonal antibody. Serum fetuin-A levels were lower in patients with calcific aortic stenosis as compared to the control group (1.41+/-0.33 versus 1.57+/-0,27 mg/dl; p=0.046). This difference was particularly evident in individuals with a normal GFR >or=60 ml/min (1.36+/-0.24 versus 1.63+/-0.27 mg/dl; p=0.007). Furthermore, specific staining of fetuin-A was found in stenotic valves but not in healthy control valves. The data suggest a role of fetuin-A in the pathogenesis calcific aortic valve stenosis independently of the renal function and support the concept that mechanisms of calcium homeostasis are involved in the development of calcific aortic stenosis.

Robust association of the APOE epsilon4 allele with premature myocardial infarction especially in patients without hypercholesterolaemia: the Aachen study

BACKGROUND

Genetic influence on the manifestation of coronary artery disease (CAD) and myocardial infarction (MI) has been shown previously. From many candidate genes the APOE (apolipoprotein E) with the major alleles epsilon2/epsilon3/epsilon4 is in the focus of interest.

MATERIALS AND METHODS

In 1817 patients admitted for their first left heart catheterization at a premature age (males < 55 and females < 65) the association of APOE alleles with MI was analysed. Genotyping was done by 5' exonuclease assay (TaqMan). RESULTS APOE was significantly associated with hypercholesterolaemia (epsilon4 72% vs. epsilon3 66% vs. epsilon2 51%; P < 0.0001), and premature MI (epsilon4 57% vs. epsilon3 50% vs. epsilon2 41%; P < 0.0001; hazard ratio 1.41, 95%CI 1.14-1.75). In patients without hypercholesterolaemia, the APOE allele epsilon4 was highly predictive for the presence of premature MI (epsilon4 55% vs. epsilon3 45% vs. epsilon2 28%; P < 0.0001; hazard ratio 1.75, 95%CI 1.19-2.57).

CONCLUSION

The APOEepsilon4 allele shows a robust association with premature MI independent of hypercholesterolaemia.

A double-blind, randomized, placebo-controlled multicenter clinical trial to evaluate the effects of the angiotensin II receptor blocker candesartan cilexetil on intimal hyperplasia after coronary stent implantation

BACKGROUND

Preclinical data suggest beneficial effects of angiotensin II receptor blockers (ARBs) on neointima formation after vascular injury. Preliminary clinical data, however, revealed conflicting results. The AACHEN trial was a double-blind, randomized, placebo-controlled clinical multicenter trial to evaluate the effects of candesartan cilexetil on intimal hyperplasia after coronary stent implantation.

METHODS

A total of 120 patients (61 +/- 9 years, 83% male) were randomized to receive either 32 mg candesartan cilexetil (active) or placebo starting 7 to 14 days before elective coronary stent implantation. A follow-up angiography including intravascular ultrasound assessment of the target lesion was performed 24 +/- 2 weeks after stent implantation. The primary end point was defined as the difference in neointimal area between groups as assessed by intravascular ultrasound. Secondary end points included differences in angiographic parameters (ie, restenosis rate) and incidence of major cardiac events.

RESULTS

The mean stent length measured 15.0 +/- 4.9 mm in the active and 14.6 +/- 5.7 mm in the placebo group (P = .81). There was no significant difference in neointimal area between groups (2.1 +/- 1.0 vs 2.1 +/- 1.5 mm2, P = 1.00), nor were there differences in angiographic end point parameters. Major cardiac event rates were not significantly different between treatment groups (8% vs 11%, P = .75).

CONCLUSIONS

High-dose candesartan cilexetil therapy in patients with symptomatic coronary artery disease undergoing coronary stent implantation does not reduce clinical event rates, restenosis rates, or neointimal proliferation after elective stent implantation.

Relationship of five inflammatory gene polymorphisms with morbidity and mortality in 533 patients admitted to an ICU

BACKGROUND

The aim of this study was to analyze the association of polymorphisms of five candidate genes with the outcome of consecutive patients admitted to a medical ICU.

MATERIALS AND METHODS

The study population was prospectively recruited. Inclusion criteria were admission to the ICU and written informed consent by the patients or their relatives. A total of 533 patients were recruited. The morbidity was assessed by SAPS II Score. Outcome data of in hospital mortality and length of ICU and hospital stay were obtained. Genotyping for genetic polymorphisms (CRP 1059, IL1B -511, CTGF -477, CCR2 64VI, IL6 -174) were performed by allele-specific fluorogenic oligonucleotide probes (TaqMan analysis).

RESULTS

All of the investigated polymorphisms were not associated with an altered outcome. There was no difference in morbidity and ICU or in-hospital mortality (neither in cross tabs analysis nor in Kaplan Meier or Cox regression analysis including age, gender and diagnosis as covariates) between the different genotypes.

CONCLUSIONS

Genotyping of the investigated polymorphism for risk stratification of patients admitted to ICU does not seem to be appropriated.

Obesity is associated with a slower response to initial phenprocoumon therapy whereas CYP2C9 genotypes are not

BACKGROUND

Initiation of phenprocoumon therapy is associated with a variable individual response. The CYP2C9 genotype has been shown to influence the response to warfarin therapy, but such an effect on phenprocoumon therapy remains uncertain.

METHOD

Two hundred sixty hospital patients started on phenprocoumon were recruited for this study. Body mass index (BMI), waist and hip circumference, dietary habits, comorbidity, and comedication were initially assessed. A 5' exonuclease assay (TaqManR) was used to analyze the presence of five polymorphisms of the CYP2C9 gene in each of the study patients. Study endpoints included the time necessary to achieve the international normalized ratio (INR) target (INR >2) and the total drug amount required to attain target INR. For 250 of 260 patients, the subsequent required daily maintenance dose of phenprocoumon was also recorded.

RESULTS

Both the necessary time and total dose required to attain target INR correlated significantly with BMI. The leaner the patient, the shorter the required time interval [BMI <22 (n=31), 5.48+/-2.49 days; BMI 22-25 (n=70), 6.09+/-2.40; BMI 25-30 (n=113), 6.76+/-3.61; BMI >30 (n=46), 8.50+/-5.75; p=0.001] and the lower the required dosage until the therapeutic range was achieved [BMI <22 (n=31), 23.8+/-12.1 mg; BMI 22-25 (n=70), 25.9+/-11.4 mg; BMI 25-30 (n=113), 29.6+/-25.2; BMI >30 (n=46), 35.8+/-19.7; p=0.027]. Overweight and waist circumference as a surrogate marker for abdominal fat were also associated significantly with these two parameters. Moreover, obesity was associated with a lower body-weight-adjusted maintenance dosage. All CYP2C9 genotypes that were tested failed to reveal an association with individual response variability.

CONCLUSION

Patient obesity appears to directly correspond to the amount of phenprocoumon required during initiation of therapy. The CYP2C9 genotype was not shown to influence the necessary therapeutic dosage.

Lower serum calcium levels are associated with greater calcium hydroxyapatite deposition in native aortic valves of male patients with severe calcific aortic stenosis

BACKGROUND AND AIM OF THE STUDY

The study aim was to evaluate the relationship between serum calcium levels and the degree of calcification found in stenotic aortic valves.

METHODS

Using atomic absorption spectroscopy, the hydroxyapatite content of 228 excised human stenotic aortic valves was determined and expressed as a percentage of valve mass. Left heart catheterization preceded valve replacement. In addition, serum levels of calcium and creatinine were determined before native calcific aortic valve excision.

RESULTS

Valves from male patients contained more hydroxyapatite than those of female patients (26 +/- 9 versus 22 +/- 9 mass%; p < 0.001). Patients presenting with lower serum calcium levels showed a slight trend towards higher levels of valve calcification (r = -0.15, p = 0.026), but this association appeared only within the subgroup of male patients. Male patients with lowest serum calcium levels displayed greatest valvular hydroxyapatite deposition (1st calcium tertiary: 29.5 +/- 8.9 mass% versus 2nd calcium tertiary 26.4 +/- 7.8 mass% versus 3rd calcium tertiary 21.4 +/- 8.9 mass%; n = 122; p = 0.001; r = -0.25; p = 0.006). This association was even more distinct in male patients with normal serum creatinine levels. Furthermore, serum calcium was inversely and significantly associated with serum C-reactive protein in male patients (r = - 0.34; p < 0.001).

CONCLUSION

Serum calcium levels appear to be inversely related to valve calcification in patients with severe calcific aortic stenosis (AS). This finding indicates the importance of systemic calcium metabolism in calcific AS, independent of manifest disorders of calcium metabolism or renal function. Interestingly, this association was evident only in male patients, suggesting a gender-dependent pathogenesis.

Quantification of Aortic Valve Calcification Using Multislice Spiral Computed Tomography

OBJECTIVES

Multislice spiral computed tomography (MSCT) allows the in vivo detection of valvular calcification. The aim of this study was to validate the quantification of aortic valve calcification (AVC) by MSCT with in vitro measurements by atomic absorption spectroscopy.

METHODS

In 18 patients with severe aortic stenosis, 16 detector row MSCT (SOMATOM Sensation 16, Siemens, Forchheim, Germany with scan parameters as follows: 420 milliseconds tube rotation time, 12 x 0.75 mm collimation, tube voltage 120 KV) was performed before aortic valve replacement. Images were reconstructed at 60% of the RR interval with an effective slice thickness of 3 mm and a reconstruction increment of 2 mm. AVC was assessed using Agatston AVC score, mass AVC score, and volumetric AVC score. After valve replacement, the calcium content of the excised human stenotic aortic valves was determined in vitro using atomic absorption spectroscopy.

RESULTS

The mean Agatston AVC score was 3,842 +/- 1,790, the mean volumetric AVC score was 3,061 +/- 1,406, and mass AVC score was 888 +/- 492 as quantified by MSCT. Atomic absorption spectroscopy showed a mean true calcification mass (Ca5(PO4)3OH) of 19 +/- 8 mass%. There was a significant correlation between in vivo AVC scores determined by MSCT and in vitro mean true calcification mass (r = 0.74, P = 0.0004 for mass AVC score, r = 0.79, P = 0.0001 for volumetric AVC score and r = 0.80, P = 0.0001 for Agatston AVC score) determined by atomic absorption spectroscopy. Linear regression analysis showed a significant association between the degree of hydroxyapatite (given in mass%) in the aortic valve and the degree of AVC (R = 0.74, F = 19.6, P = 0.0004 for mass AVC score, R = 0.80, F = 29.3, P = 0.0001 for Agatston AVC score and R = 0.79, F = 27.3, P = 0.0001 for volumetric AVC score) assessed by MSCT.

CONCLUSION

MSCT allows accurate in vivo quantification of aortic valve calcifications.

APOE alleles are not associated with calcific aortic stenosis

OBJECTIVES

To analyse the association of APOE alleles with aortic stenosis (AS) in a large study population.

METHODS

Patients with AS (n = 538) and a control group of the same age without heart disease (n = 536) were recruited. Left heart catheterisation was performed and mean gradient, aortic valve area, presence of stenotic coronary artery disease (CAD) and cardiovascular risk factors (hypercholesterolaemia, hypertension, smoking, diabetes mellitus and family history of CAD) were assessed. The frequency of the APOE major alleles e2, e3 and e4 was assessed by genotyping the polymorphisms APOE334 and APOE472 with a 5' exonuclease assay (TaqMan).

RESULTS

Mean gradient across the aortic valve in cases was 50 (SD 20) mm Hg corresponding to a mean aortic valve area of 0.84 (SD 0.34) cm(2). 270 patients with AS had stenotic CAD. Among patients with AS, the prevalence of hypercholesterolaemia (64% v 40%, p < 0.001), smoking (43% v 27%, p < 0.001), diabetes (27% v 17%, p < 0.01), family history of CAD (30% v 21%, p </= 0.05), and male sex (65% v 44%, p < 0.001) was higher in those with than in those without CAD. The frequency of the major alleles was not different between cases and controls (APOE e2: 104 (19.3%) v 94 (17.5%); APOE e3: 319 (59.3%) v 332 (61.9%); APOE e4: 115 (21.3%) v 110 (20.5%); all p > 0.10).

CONCLUSION

APOE e4 is not associated with AS, reflecting the different genetic backgrounds of CAD and AS.

Prevalence of atherosclerosis of the coronary and extracranial cerebral arteries in patients undergoing aortic valve replacement for calcified stenosis

BACKGROUND AND AIM OF THE STUDY

The study aim was to investigate the coexistence of various atherosclerotic changes in patients with non-rheumatic calcific aortic valve stenosis (AS), since calcific AS shares various clinical risk factors with atherosclerosis.

METHODS

In 282 consecutive patients with severe calcific stenosis of a tricuspid aortic valve scheduled for aortic valve replacement, the prevalence of atherosclerotic changes of the coronary and extracranial cerebral arteries were assessed using coronary angiography and Doppler sonography, respectively.

RESULTS

The severities of coronary and extracranial cerebral artery atherosclerosis were significantly associated (p = 0.005). The prevalence and severity of both coronary and extracranial cerebral artery atherosclerosis were age-dependent. Coronary or extracranial cerebral artery stenosis was present in 59% and 16% of patients, respectively, while 91% of the study population and all patients aged > 80 years showed atherosclerosis of the coronary and/or extracranial cerebral arteries.

CONCLUSION

The data obtained indicated a very high prevalence of atherosclerotic changes in patients with calcific AS, suggesting pathogenetic similarities of both disorders. Routine screening of the extracranial cerebral arteries is warranted in all patients with calcific AS and scheduled for valve replacement.

Additive effects of the chemokine receptor 2, vitamin D receptor, interleukin-6 polymorphisms and cardiovascular risk factors on the prevalence of myocardial infarction in patients below 65 years

BACKGROUND

Cardiovascular risk factors (CRF) have been associated with myocardial infarction (MI), while the role of genetic risk factors (GRF) remains undetermined.

METHODS

Cineventriculograms of 3436 were analyzed for presence of regional function impairment as sign of MI. Genotyping for genetic polymorphism (vitamin D receptor VDR BsmI, interleukin-6 IL6-174 G/C, chemokine receptor 2 CCR2 64 V/I) was performed. CRF were assessed (hypertension, hypercholesterolemia, smoking, and diabetes mellitus).

RESULTS

In patients <65 years (n=1946) genotypes (VDR BB, IL6 GC/CC, CCR2 VI/II, defined as GRF) were significantly associated with the presence of MI (BB: OR 1.38, 95%CI 1.07-1.79, p=0.016 GC/CC: 1.28, 95%CI 1.03-1.60, p=0.028 VI/II: 1.49, 95%CI 1.17-1.88, p=0.001). Combining four CRF (14% vs. 21% vs. 27% vs. 31% vs. 38%, p<0.0001) and three GRF (21% vs. 25% vs. 32% vs. 44%, p<0.0001) revealed additive effects on the prevalence of MI. The more combined CRF and GRF were present (from 0 to 7) the higher was the prevalence of MI (11% vs. 12% vs. 21% vs. 27% vs. 30% vs. 34% vs. 59%, p< 0.0001). Age was not associated with MI. In patients > or =65 years (n=1490) the combination of CRF was only weakly associated with MI, while GRF were not. In these patients age was a predictor of MI.

CONCLUSION

Certain GRF might have additive but small effects on the disposition for MI before the age of 65. In older patients the tested GRF had no effect, possibly indicating a mechanism of aging rather than a purely genetic determined entity. Given the small effect of the tested genetic polymorphisms the value of testing GRF remains uncertain.

Relationship between physical fitness and lifestyle behaviour in healthy young men

BACKGROUND

There is substantial knowledge about the inverse association of physical fitness and CVD risk factors and CVD mortality. However, physical fitness per se might be influenced by lifestyle conditions such as physical training, smoking and drinking habits.

HYPOTHESIS

We evaluated the relationship between physical fitness, physical activity, endurance training, smoking and drinking habits and blood pressure, lipids and leukocytes as surrogate cardiovascular risk markers in a large-scale cross-sectional study of healthy young men.

STUDY DESIGN AND METHODS

A total of 6748 healthy young men were selected during their primary flight medical examination for military flying duties. Physical fitness was assessed by achieved physical working capacity at a heart rate of 170 beats per min (PWC170) during cycle ergometry. Parameters such as physical activity, endurance sports, smoking of cigarettes and drinking of alcoholic beverages were assessed by means of standardized questionnaires. Systolic and diastolic blood pressures were measured manually. Fasting cholesterol and triglycerides as well as white blood counts were obtained.

RESULTS

Physical activity itself was not related to significant differences in the tested variables, whereas good physical fitness showed a significant association with improved blood pressure and blood lipids (P<0.001) with no detectable threshold. This effect was independent of endurance training, smoking and drinking. Whereas drinking was associated with elevated systolic blood pressure, smoking was associated with markedly increased triglycerides as well as with elevated leukocytes.

CONCLUSION

Physical fitness is associated with improved blood pressure and blood lipids. This effect is independent of participating mainly in endurance or nonendurance sports, of physical activity per se, and it does not depend on smoking and drinking habits. Smoking itself revealed relevant higher inflammation independent of fitness.

Intravascular ultrasonic comparative analysis of degree of intimal hyperplasia produced by four different stents in the coronary arteries

Intravascular ultrasound studies were performed at angiographic follow-up on 121 native coronary lesions treated with 1 bare metal stent (n = 50), high-dose dexamethasone-eluting stents (n = 18), non-polymer-based paclitaxel-eluting stents (n = 18), or sirolimus-eluting stents (n = 35). Paclitaxel- and sirolimus-eluting stents reduced mean intimal hyperplasia thickness compared with bare metal stents by 49% and 90% (p = 0.048 and p <0.001), respectively, whereas mean intimal hyperplasia thickness treated with dexamethasone-eluting stents was similar to those lesions treated with bare metal stents.

The amount of calcium-deficient hexagonal hydroxyapatite in aortic valves is influenced by gender and associated with genetic polymorphisms in patients with severe calcific aortic stenosis

AIMS

The study evaluated the relationship between cardiovascular risk factors (CRF), gene polymorphism, calcification and fibrosis of stenotic aortic valves.

METHODS AND RESULTS

The calcium content of 187 excised stenotic aortic valves was determined using atomic absorption spectroscopy. Hydroxyproline content was quantified. Left-heart catheterization was performed. CRF and genotypes of the interleukin 10, connective tissue growth factor (CTGF) and chemokine receptor 5 (CCR5) polymorphisms were assessed. Calcification consisted of Ca-deficient hexagonal hydroxyapatite, Ca(10 - x)(HPO4)x(PO4)(6 - x)(OH)(2 - x); with 0<or=x<or=1. Calcification (quintiles) was positively associated with the mean gradient across the aortic valve (44 +/- 14, 52 +/- 17, 54 +/- 16, 60 +/- 15, 68 +/- 19 mm Hg; p<0.001). Males (n=101) had a higher degree of calcification (26.1 +/- 8.9 vs 20.8 +/- 9.2 mass%; p<0.001), despite the same mean gradient across the aortic valve (56 +/- 17 vs 56 +/- 19 mm Hg; p=0.958). CRF were not, whereas interleukin 10 polymorphisms -1082, -819, and -592 were significantly associated with the degree of calcification. Furthermore, if certain allele carriers had additionally the rare CCR5 or CTGF allele the degree of calcification was higher.

CONCLUSION

Calcification of stenotic aortic valves consists of Ca-deficient hexagonal hydroxyapatite. Gender and genetic polymorphisms have an impact on the degree of aortic valve calcification.

Cardiovascular risk factors in patients with aortic stenosis predict prevalence of coronary artery disease but not of aortic stenosis: an angiographic pair matched case-control study

BACKGROUND

Traditional cardiovascular risk factors have been associated with aortic stenosis and coronary artery disease. As these two conditions often co-exist, the association of cardiovascular risk factors with aortic stenosis may reflect confounding.

OBJECTIVE

To compare the cardiovascular risk profile in patients with severe aortic stenosis undergoing elective coronary angiography with that of patients without aortic stenosis or calcification undergoing coronary angiography for suspected coronary artery disease.

METHODS

523 patients referred for elective diagnostic left heart catheterisation because of severe aortic stenosis formed the case population; 3925 patients without valve disease referred for elective diagnostic left heart catheterisation formed the base control population. Of the latter, 523 were pair matched to the case population for sex, age, and prevalence of relevant coronary artery disease, forming a pair matched control population. Cardiovascular risk factors (male sex, hypertension, hypercholesterolaemia, smoking, diabetes mellitus, family history of coronary artery disease) were assessed in all the patients.

RESULTS

None of the cardiovascular risk factors was more prevalent in patients with aortic stenosis than in the base control population or in the pair matched control population. However, male sex, hypercholesterolaemia, smoking, diabetes mellitus, and a family history of coronary artery disease were significantly associated with the presence of additional coronary artery disease in patients with aortic stenosis.

CONCLUSIONS

Cardiovascular risk factors are commonly present in patients with aortic stenosis. However, when compared with controls matched for age, sex, and angiographically defined coronary artery disease, no risk factor was significantly associated with the prevalence of aortic stenosis. Thus other factors are likely to be more important in the pathogenesis of aortic stenosis.

The interleukin-6 promoter polymorphism is associated with elevated leukocyte, lymphocyte, and monocyte counts and reduced physical fitness in young healthy smokers

Smoking and interleukin-6 are important factors in driving inflammation. This study assessed the relationship between smoking, interleukin-6 genotype, physical fitness, and peripheral blood count in healthy young men. For this interleukin-6 promoter polymorphism -174 genotype-phenotype association study 1,929 healthy German male aviators recruited at the central German Air Force Institute of Aviation Medicine were stratified by smoking habits. Cardiovascular fitness was expressed as maximal physical working capacity (PWCmax) in watts per kilogram body weight as assessed by maximal exercise testing by cycle ergometry up to physical exhaustion. Smokers had higher leukocyte and lymphocyte counts than nonsmokers and lower PWCmax. In the overall study population the C allele of the interleukin-6 polymorphism was weakly associated with elevated leukocytes and lymphocytes; in nonsmokers the interleukin-6 polymorphism was not associated with altered phenotypes, but in smokers the interleukin-6 C allele was associated with higher leukocytes, lymphocytes, and monocytes and with lower PWCmax. Smoking is thus associated with elevated leukocytes and lymphocytes and with reduced physical fitness. Gene carriers with the interleukin-6 C allele may suffer particularly from cigarette smoking.

Relation between the angiotensinogen (AGT) M235T gene polymorphism and blood pressure in a large, homogeneous study population

The aim of this study was to assess the association of the angiotensinogen M235T polymorphism with arterial blood pressure (BP) at rest and under physical stress in a homogeneous large-scale study population. In all, 1903 men who passed routine medical examination for military flying duty were recruited. BP and heart rate were measured at rest, during, and after bicycle ergometry. Genotyping for the AGT M235T polymorphism was carried out by PCR and RFLP technique. The AGT T235 allele was associated with a significantly higher diastolic BP (n=1903; MM 81+/-8, MT 83+/-7, TT 83+/-8; P=0.003). Pulse pressure (PP) at rest differed significantly between AGT genotypes (n=1903; MM 51+/-10 mmHg, MT 49+/-10 mmHg, TT 49+/-10 mmHg; P=0.001). During physical activity, BP values showed no significant difference between genotypes. In healthy young men, the AGT T235 allele is significantly associated with elevated diastolic BP but also reduced PP at rest. During physical activity, the AGT polymorphism had no impact on blood pressure, indicating the existence of other counteracting mechanisms, which might balance the influence of this gene.

Relation of body mass index, physical fitness, and the cardiovascular risk profile in 3127 young normal weight men with an apparently optimal lifestyle

Obesity is a well-accepted cardiovascular risk factor associated with hypertension and hyperlipidaemia. A body mass index (BMI) within the range of 18.5-25 kg/m(2) is considered normal. To prevent cardiovascular diseases regular physical activity and abstinence from smoking are strongly recommended. Since it is not evident that a lower optimal threshold exists concerning cardiovascular risk factors if other lifestyle conditions are apparently optimised, we studied the relation between BMI and vascular risk factors in 3127 hyperhealthy Caucasian males. They were aged between 18 and 23 y, were nonsmokers, without regular alcohol intake, and had at least 3 h of sports activity per week. Their BMI was below 25 kg/m(2). Low BMI revealed to be significantly associated with high physical fitness, low blood pressure, and low serum lipids. The lower the BMI was, the more favourable these parameters were. Thus, the threshold for an optimal BMI concerning cardiovascular risk factors might be far below 25 kg/m(2) even if other lifestyle conditions are apparently optimal.

Chemokine receptor (CCR2) genotype is associated with myocardial infarction and heart failure in patients under 65 years of age

Inflammation is associated with atherosclerosis of coronary arteries. Chemokines have an important role in inflammation. The CCR2 chemokine receptor mediates leukocyte chemoattraction, which is involved in the pathogenesis of coronary heart disease. We prospectively studied 1960 consecutive patients aged under 65 years and referred for a first-time left ventricular catheter. Left heart catheters were analyzed by two independent cardiologists for the presence of myocardial infarction (regional wall motion abnormality) and moderate or severely reduced left ventricular function on cineventriculography and presence of coronary atherosclerosis on angiography. Genotyping for CCR2 V64I polymorphism was performed. The presence of the rare allele of the CCR2 gene was significantly associated with a higher prevalence of myocardial infarction on cinventriculography (32.0% vs. 24.2%, moderately or severely reduced left ventricular function (14.0% vs. 9.5%) and NYHA class III or IV (16.7% vs. 12.2%). The association of the CCR2 genotype with heart failure was not independent of the presence of myocardial infarction in multivariate analysis. There was no association of the CCR2 genotype with coronary atherosclerosis. The CCR2 genotype seems to predispose patients for myocardial infarction before the age of 65 years. The higher prevalence of heart failure in gene carriers with the rare alle might be a consequence of myocardial infarction. If the CCR2 genotype is associated with higher mortality in the general population must be investigated in further studies.

The vitamin D receptor gene variant and physical activity predicts fasting glucose levels in healthy young men

AIMS

Vitamin D can influence lipolysis and insulin secretion. A common genetic polymorphism of the vitamin D receptor (VDR), which has been found to be associated with bone mineral density, has been reported to be also associated with Type 2 diabetes mellitus (DM). To test the influence of the VDR polymorphism on fasting glucose in healthy young men before the onset of Type 2 DM, we studied a homogeneous population of aircrew members.

METHODS

A total of 1539 individuals were recruited during routine medical qualification for flying duty. Physical activity was assessed in all individuals and categorized into low physical activity (<or= 3 h per week) and high physical activity (> 3 h per week). The BsmI VDR polymorphism was analysed by polymerase chain reaction. On the day of blood testing the individuals were fasting for at least 8 h overnight. Serum glucose was measured within 60 min after sampling venous blood.

RESULTS

In young males with low physical activity (n = 752) gene carriers with the VDR genotype BB (n = 137) have significantly (P < 0.001) higher levels of fasting glucose (5.61 +/- 0.49 mmol/l) than gene carriers with the genotype Bb (n = 370; 5.44 +/- 0.44 mmol/l) or bb (n = 245; 5.38 +/- 0.44 mmol/l). Of BB gene carriers, 47% had fasting glucose levels > 5.55 mmol/l compared with 36% of Bb gene carriers and 34% of bb gene carriers (P = 0.018). This effect is absent in gene carriers with high physical activity (n = 787).

CONCLUSIONS

The VDR genotype is associated with altered fasting glucose levels in young men with low physical activity. If this association is confirmed in other populations it might be worthwhile studying the particular benefits of an exercise programme in dependents of the VDR genotype.

Vitamin D receptor gene polymorphism BsmI is not associated with the prevalence and severity of CAD in a large-scale angiographic cohort of 3441 patients

BACKGROUND

Recent studies found a relationship between Vitamin D and atherosclerosis. A common genetic polymorphism of the Vitamin D receptor (VDR) has been associated with coronary artery disease (CAD) in small study populations. To assess its influence on the prevalence and severity of CAD we studied a large-scale population.

METHODS

A total of 3441 consecutive patients were referred for diagnostic coronary angiography. The BsmI Vitamin D receptor polymorphism was analyzed by polymerase chain reaction. Angiography was used to define phenotypes with clear coronary arteries (n = 775), coronary sclerosis (diameter stenosis < 50%; n = 579), CAD (diameter stenosis > 50% in at least one vessel; n = 1524). Patients with CAD at a young age (females aged less than 65 years, males aged less than 55 years; n = 563) were specially defined as premature CAD. The risk profile of traditional cardiovascular risk factors was obtained for every patient.

RESULTS

The genotype frequencies of the VDR BsmI polymorphism did not differ between all four phenotypes (P = 0.756). The allele frequencies for the B allele were 0.43 vs. 0.44 vs. 0.42 vs. 0.45 in the four phenotypic groups (P = 0.827). All traditional cardiovascular risk factors (hypercholesterolaemia, smoking, hypertension, diabetes mellitus, severe obesity, male gender) were significantly (P < 0.001) associated with the angiographic phenotype.

CONCLUSIONS

The VDR gene variant BsmI was not associated with prevalence and severity of CAD in a large-scale cohort phenotyped by angiography.

Analysis of several hundred genetic polymorphisms may improve assessment of the individual genetic burden for coronary artery disease

BACKGROUND: Single polymorphisms of different genes have been associated with coronary artery disease (CAD). The aim of this study was to evaluate the benefit of analyzing multiple genetic polymorphisms as a compound unit to assess the individual genetic burden for CAD. METHODS AND RESULTS: The study population consisted of 100 case patients with, and 100 control patients without, angiographically proven CAD. The patients were matched for age, sex, and numbers of standard cardiac risk factors. Sixteen different genetic polymorphisms were analyzed using polymerase chain reaction-based technologies. None of these polymorphisms showed a significant difference in the allele frequency between case and control patients. Eight genes with a higher allele frequency in the case group (delta allele frequency >0.05) were defined as risk alleles (RA) and subsequently tested as a compound unit. A risk stratification for 64.5% of all patients was possible when eight genes with their 16 RA were included in the analysis. With more than eight RA per individual, the odds ratio for developing CAD was 3.21 (95% CI 1.77-5.82, P<0.001). However, there was still an overlap in the number of RA in case and control patients. A computer simulation estimated that more than 200 polymorphisms were needed for a reasonable genetic discrimination for patients at risk for CAD. CONCLUSIONS: An increasing number of risk alleles are associated with an elevated risk for CAD. An analysis of multiple polymorphisms, some several hundred, each with a small impact, may allow improved assessment of the individual genetic burden for CAD. Larger studies are needed to prove this hypothesis.

Variants of the CYP11B2 gene predict response to therapy with candesartan

In a prospective trial, patients with an elevated diastolic blood pressure (above 95 mm Hg) received high-dose (16 mg) or low-dose (8 mg) candesartan in addition to standardised medication. A positive response to treatment was defined as a diastolic blood pressure <85 mm Hg at follow-up. Genotyping for two candidate genes was performed in 116 patients. Genotypes of the CYP11B2 promotor polymorphism significantly predicted a positive response to treatment (CC: 67%; TC: 34%; TT: 21%; p=0.005).

Genetic polymorphisms in the renin-angiotensin-aldosterone system associated with expression of left ventricular hypertrophy in hypertrophic cardiomyopathy: a study of five polymorphic genes in a family with a disease causing mutation in the myosin binding protein C gene

BACKGROUND

Hypertrophic cardiomyopathy (HCM) is an inherited disease of the sarcomere characterised clinically by myocardial hypertrophy and its consequences. Phenotypic expression is heterogeneous even within families with the same aetiological mutation and may be influenced by additional genetic factors.

OBJECTIVE

To determine the influence of genetic polymorphisms of the renin-angiotensin-aldosterone system (RAAS) on ECG and two dimensional echocardiographic left ventricular hypertrophy (LVH) in genetically identical patients with HCM.

PATIENTS AND METHODS

Polymorphisms of five RAAS components were determined in 26 gene carriers from a single family with HCM caused by a previously identified myosin binding protein C mutation. Genotypes associated with a higher activation status of the RAAS were labelled "pro-LVH genotypes".

RESULTS

There was a non-biased distribution of pro-LVH genotypes in the gene carriers. Those without pro-LVH genotypes did not manifest cardiac hypertrophy whereas gene carriers with pro-LVH genotypes did (mean (SD) left ventricular muscle mass 190 (48) v 320 (113), p = 0.002; interventricular septal thickness 11.5 (2.0) v 16.4 (6.7), p = 0.01; pathological ECG 0% (0 of 10) v 63% (10 of 16), respectively). Multivariate analysis controlling for age, sex, and hypertension confirmed an independent association between the presence of pro-LVH polymorphisms and left ventricular mass. When each polymorphism was assessed individually, carriers of each pro-LVH genotype had a significantly greater left ventricular mass than those with no pro-LVH mutation; these associations, with the exception of cardiac chymase A AA polymorphism (p = 0.06), remained significant in multivariate analysis.

CONCLUSION

Genetic polymorphisms of the RAAS influence penetrance and degree of LVH in 26 gene carriers from one family with HCM caused by a myosin binding protein C mutation.

Inhibition of the renin-angiotensin system ameliorates genetically determined hyperinsulinemia

This study was performed in order to assess the potentially different effects of the angiotensin-converting enzyme inhibitor captopril and of the angiotensin II receptor antagonist irbesartan on the metabolic syndrome in an animal model. Male NZO/BL6 F1 mice were treated with captopril, irbesartan, or placebo for 10 months: Control animals treated with placebo developed a metabolic syndrome with obesity (55.5+/-6.3 g), hypertension (146+/-10 mm Hg), hyperinsulinemia (7.2+/-5.7 ng/ml), hypercholesterolemia (5.1+/-0.7 mmol/l), cardiac hypertrophy (269+/-44 mg) and atherosclerotic plaques in the ascending aorta (3.6+/-1.5 microm(2)). Treatment with angiotensin-converting enzyme inhibitor or angiotensin II receptor antagonist significantly (p<0.001) reduces hypertension (73+/-5 and 78+/-11 mm Hg), cardiac hypertrophy (203+/-26 and 202+/-18 mg) and atherosclerosis (2.2+/-0.9 and 1.8+/-0.8 microm(2)). In addition, they prevented the development of obesity (42.2+/-3.5 and 38.3+/-2.8 g) and hyperinsulinemia (3.6+/-1.5 and 1.8+/-0.4 ng/ml). In conclusion, long-term treatment with an angiotensin-converting enzyme inhibitor or an angiotensin II receptor antagonist can ameliorate obesity and hyperinsulinemia in a genetically determined mouse model.

The vitamin D receptor gene variant is associated with the prevalence of type 2 diabetes mellitus and coronary artery disease

AIMS

Vitamin D can influence lipolysis and insulin secretion. A common genetic polymorphism of the vitamin D receptor, which has been found to be associated with bone mineral density, has also been reported to be associated with insulin-dependent diabetes mellitus. To test the influence of the vitamin D receptor polymorphism on the prevalence of Type 2 diabetes mellitus and coronary artery disease we studied a population of high-risk patients, who were referred to our clinic for diagnostic coronary angiography.

METHODS

A total of 293 patients considered at high risk for coronary artery disease because of angina pectoris and known hypercholesterolaemia underwent diagnostic coronary angiography. The BsmI vitamin D receptor polymorphism was analysed by polymerase chain reaction.

RESULTS

Prevalence of Type 2 diabetes mellitus and coronary artery disease was gradually dependent on the number of B alleles (BB 28%, Bb 13%, bb 8% for Type 2 diabetes mellitus, P = 0.002; BB 88% Bb 72%, bb 66% coronary artery disease, P = 0.01). Patients with the BB genotype had an odds ratio of 3.64 (95% confidence interval 1.53-8.55, P = 0.002) to have Type 2 diabetes mellitus compared with patients with the bb genotype.

CONCLUSIONS

The genotype of the vitamin D receptor polymorphism determines the prevalence of Type 2 diabetes mellitus and coronary artery disease in a high-risk cohort population.

A chymase gene variant is associated with atherosclerosis in venous coronary artery bypass grafts

BACKGROUND

Angiotensin II is known to stimulate proliferation of fibroblasts and smooth muscle cells and enhance the atherosclerotic process in native coronary arteries. The impact of genetic polymorphisms of the renin-angiotensin-aldosterone system on coronary bypass graft degeneration is unknown.

METHODS

We examined polymorphisms of four genes (AGTR1, CYP11B2, ACE, CMA) in 101 patients who had follow-up coronary angiography due to symptoms 88 +/- 52 months after coronary artery bypass graft surgery. Bypass degeneration was determined with quantitative coronary angiography and an adjusted Gensini score.

RESULTS

Homozygosity for the G allele of the CMA-1905 polymorphism was associated with a higher degree of bypass degeneration (Bypass Gensini score CMA AA 21.4 +/- 39; AG 24.2 +/- 39.8; GG 27.8 +/- 42.3; NS-time adjusted Gensini bypass scores CMA AA 0.25 +/- 0.68; AG 0.57 +/- 1.82; GG 3.25 +/- 13.2; P = 0.005). No association could be detected for the AGTR1, CYP11B2 or ACE polymorphism.

CONCLUSION

The CMA allele G is a genetic risk factor for atherosclerosis in venous coronary artery bypass grafts. Its importance has to be shown in further studies. Other polymorphisms of the renin-angiotensin-aldosterone system do not seem to play a role in bypass degeneration.

The vitamin D receptor genotype predisposes to the development of calcific aortic valve stenosis

OBJECTIVE

To test the hypothesis that vitamin D receptor polymorphism is associated with calcific aortic valve stenosis.

DESIGN

The distribution of one polymorphism of the vitamin D receptor (BsmI B/b) was examined in 100 consecutive patients with calcific valvar aortic stenosis and compared with a control group of 100 patients (paired match for age, sex, and the presence of coronary artery disease from a total of 630 patients without calcified aortic valves). Polymerase chain reaction and restriction fragment length polymorphism were used to determine genotypes.

RESULTS

There was a significant difference in vitamin D receptor allele and genotype frequencies between the two groups. The allele B had a higher prevalence in patients with calcific aortic stenosis (B = 0.56, b = 0.44) than in the control cohort (B = 0.40, b = 0.60) (p = 0.001).

CONCLUSIONS

There is a significant association of vitamin D receptor polymorphism with calcific aortic valve stenosis. The B allele of the vitamin D receptor is more common in patients with calcific aortic valve stenosis. It now needs to be evaluated whether other genes that control calcium homeostasis are involved in the pathogenesis of this disorder.

Lack of association among five genetic polymorphisms of the renin-angiotensin system and cardiac hypertrophy in patients with aortic stenosis

BACKGROUND

Patients with aortic stenosis (AS) have left ventricular hypertrophy (LVH). It is thought that LVH in these patients is a consequence of chronic left ventricular pressure overload. However, there is only a poor correlation between the degree of AS and the degree of LVH. Genetic polymorphisms of the renin-angiotensin-aldosterone system (RAAS) have been considered to trigger the response of the left ventricle to chronic pressure overload and determine the degree of LVH in patients with AS.

METHODS

One hundred five consecutive patients with symptomatic AS were examined by echocardiography and left heart catheterization to determine the severity of AS and LVH. Five genetic polymorphisms of the RAAS (ACE, AGTR1, AGT, CMA, CYP11B2) were analyzed in all patients and the results of genetic analysis were correlated to severity of AS and LVH to determine the importance of the polymorphisms for LVH.

RESULTS

All tested genotypes were in Hardy-Weinberg equilibrium and allele frequencies were similar to other study populations. There was no correlation between the severity of AS and the severity of LVH. There was no association between the five tested genotypes of the RAAS and the severity of AS (mean gradient and area of the aortic valve) or LVH (LV muscle mass).

CONCLUSION

We conclude that LVH in patients with AS is not determined by the tested genetic polymorphisms of the RAAS.

Quantitative trait loci for obesity and insulin resistance (Nob1, Nob2) and their interaction with the leptin receptor allele (LeprA720T/T1044I) in New Zealand obese mice

AIMS/HYPOTHESIS

To locate genes responsible for obesity and insulin resistance, a backcross model of New Zealand obese (NZO) mice with the lean Swiss/Jackson Laboratory (SJL) strain was stablished.

RESULTS

In female NZO x F1 backcross mice, two major quantitative trait loci for variables of obesity (body weight, body mass index, total body fat) and insulin resistance (hyperinsulinaemia) were identified on chromosomes 5 (Nob1) and 19 (Nob2) close to the markers D5Mit392 and D19Mit91. The aberrant alleles have presumably contributed by the NZO genome. Whereas Nob1 contributed mainly to higher body weight, Nob2 seemed to mainly aggravate insulin resistance independent of obesity. The leptin receptor variant of NZO (LeprA720T/T1044I) failed to alter any of the variables of obesity. It seemed, however, to enhance the effect of Nob1 on body weight and that of Nob2 on serum insulin concentration. When expressed in COS-7 cells, LeprA720T/T10441 produced a normal basal and maximum activation with a minor increase in the EC50 of leptin.

CONCLUSIONS/INTERPRETATION

The data identify two new quantitative trait loci that are responsible for a major part of obesity and hyperinsulinaemia as produced by recessive genes in NZO mice. LeprA720T/T1044I alone cannot produce obesity, but may enhance the effects of other obesity/insulin resistance genes in this mouse model.

Type 2 diabetes-like hyperglycemia in a backcross model of NZO and SJL mice: characterization of a susceptibility locus on chromosome 4 and its relation with obesity

A backcross model of New Zealand obese mice (NZO) with the lean, atherosclerosis-resistant SJL strain was established to locate genes responsible for obesity, insulin resistance, and type 2 diabetes-like hyperglycemia. In male NZO x F1 backcross mice, a major susceptibility locus for the development of hyperglycemia and hypoinsulinemia (Nidd/SJL) was identified on chromosome 4 between the markers D4Mit278 and D4Mit232, 10-28 cM distal of the previously described Nidd1 locus. The diabetogenic allele has presumably been contributed by the SJL genome, and it appeared to be responsible for approximately 60% of the total prevalence of hyperglycemia. The presence of Nidd/SJL did not alter body weight or weight gain by week 12. Thereafter, it was associated with reduced weight gain or weight loss, presumably as a consequence of decompensated hyperglycemia. In all male backcross mice, the prevalence of hyperglycemia at week 22 increased with the body weight at week 12, suggesting that the development of hyperglycemia was dependent on the degree of obesity. In the absence of Nidd/SJL, mice weighing <50 g at week 12 did not develop hyperglycemia by week 22. In contrast, in animals carrying the diabetogenic allele, the prevalence of hyperglycemia was 20 and 64% when the 12-week weight was <45 and 45-50 g, respectively. These data are consistent with the conclusion that Nidd/SJL represents a diabetes gene that lowers the obesity threshold for the development of hyperglycemia and hypoinsulinemia.

A metabolic syndrome of hypertension, hyperinsulinaemia and hypercholesterolaemia in the New Zealand obese mouse

BACKGROUND

New Zealand obese (NZO) mice exhibit a polygenic obesity associated with hyperinsulinaemia and hyperglycaemia. Here we show that the strain presents additional features of a metabolic syndrome, i.e. elevated blood pressure, serum cholesterol and serum triglyceride levels.

MATERIALS AND METHODS

A back-cross model of NZO mice with the lean Swiss Jackson Laboratory (SJL) strain was established in order to investigate further the correlation between hypertension, obesity, serum insulin and hyperglycaemia.

RESULTS

Systolic blood pressure was significantly elevated at 6 weeks of age and appeared to parallel the weight gain of the animals. Serum insulin levels, presumably reflecting insulin resistance, and systolic blood pressure values were significantly correlated with the body mass index (r2 = 0.707 and 0.486, respectively) in the back-cross mice. In contrast, blood pressure was only weakly correlated with serum insulin (r2 = 0.288) in non-diabetic mice, and was independent of serum insulin levels in diabetic animals.

CONCLUSION

The data are consistent with the concept that hypertension and insulin resistance are a characteristic consequence of the genetic constellation leading to obesity in the NZO strain, and that these traits reflect related mechanisms. It appears unlikely, however, that hypertension is a direct consequence of hyperinsulinaemia.