Vascular endothelial growth factor-A promoter polymorphisms, circulating VEGF-A and survival in acute coronary syndromes

BACKGROUND

Development of a competent collateral circulation in established coronary artery disease is cardio-protective. The vascular endothelial growth factor (VEGF) system plays a key role in this process. We investigated the prognostic performance of circulating VEGF-A and three genetic variants in the VEGFA gene in a clinical coronary cohort.

METHODS AND RESULTS

The Coronary Disease Cohort Study (CDCS) recruited 2,140 patients, with a diagnosis of acute coronary syndrome (ACS), after admission to Christchurch or Auckland City Hospitals between July 2002 and January 2009. We present data for 1927 patients from the cohort genotyped for three SNPs in the VEGF-A gene, rs699947 (C-2578A), rs2010963 (C405G) and rs3025039 (C936T). Plasma VEGF-A concentrations were assayed in a subgroup (n = 550) of CDCS patients (geometric mean 36.6 [34.7-38.5] pg/ml). VEGF-A levels correlated with patient heart rate at baseline (p = 0.034). None of rs699947, rs3025039, nor rs2010963 genotypes were significantly associated with VEGF-A levels, but rs3025039 genotype was positively associated with collateral vessels perfusion according to the Rentrop classification (p = 0.01) and baseline natriuretic peptide levels (p<0.05). Survival in the CDCS cohort was independently associated with baseline VEGF-A levels and (in males) with rs699947 genotype.

CONCLUSIONS

This study is strongly suggestive that VEGF-A levels have value as a prognostic biomarker in coronary heart disease patients and SNPs in VEGF-A deserve further investigation as prognostic markers and indicators of angiogenic potential influencing the formation of collateral circulation.

P1756The protein APRIL predicts adverse outcomes in DAPT patients better than NT-proBNP and troponin

Aim

Dual antiplatelet therapy (DAPT) is a mainstay of post-ACS treatment. However, prediction of adverse events in these patients needs improving. We show here that the TNFα-related protein APRIL (which is produced in platelets and atherosclerotic plaque) is a superior predictor of MACE and new MI in DAPT recipients post-ACS.

Methods

We prospectively recruited 518 patients presenting with the primary complaint of acute chest pain to our hospital ED. Patients were adjudicated to have ACS by 2 independent cardiologists in accordance with ESC guidelines with hsTnI as biomarker. Plasma EDTA samples taken at presentation and 2 hours after were interrogated for APRIL measurements using a two site ELISA. Clinical data/variables, standard biochemistry analytes, hsTnT and NT-proBNP were also measured. Statistical assessments were made using SPSS v23 (IBM). Data for all biomarkers were treated as continuous variables and are presented as median (interquartile range, (IQR)). Statistical assessment of the comparative diagnostic abilities of APRIL, hsTnT, NT-proBNP and hsTnI were assessed using receiver operator curve (ROC) area under the curve (AUC) analysis. The comparative power of each biomarker (log values) to predict new MACE, MI, bleeding and mortality in 1) the whole group and in 2) DAPT recipients alone, within 2 yrs of index presentation was undertaken using a logistic regression base model (95% CI) that included all clinical variables and hsTnI and hsTnT, with APRIL and NT-proBNP each included in additional multivariate analyses.

Results

Of the 518 recruited patients (median age 63 (IQR: 54–73, 35% female), 152 were adjudicated to have ACS (29%, 115 MI, 37 UAP). Presentation APRIL levels were higher in those with a cardiac versus non-cardiac cause for presentation (3.0, (2.0–4.7) vs. 2.4, (1.6–3.8) ng/mL, P=0.001) and positively correlated with hsTnT and NT-proBNP (all P<0.001), but it did not add to the hsTnI (ROC = 0.96) or hsTnT (ROC =0.92) assisted diagnosis of ACS. In all 518 patients, in the multivariate regression model, APRIL was a significant independent predictor of mortality (n=54, P=0.032), new MI (n=43, P=0.006), new ADHF (n=24, P=0.016) and MACE (n=71, P=0.005) that was additive to NT-proBNP and troponin. In DAPT recipients alone (n=156), APRIL was the only biomarker to independently predict new MI (n=27, 95% CI: 1.125–3.982, P=0.020) and MACE (n=37, 95% CI: 1.058–3.389, P=0.031). None of the markers, only age, predicted bleeding episodes.

Conclusion

APRIL is an platelet/plaque derived marker that provides independent risk assessment in ACS patients. In DAPT recipients, the ability of APRIL to predict new MI and MACE is superior to that of cardiac troponins and NT-proBNP and could be used to identify high risk individuals.

Acknowledgement/Funding

Health Research Council of New Zealand; Heart Foundation of New Zealand

Plasma levels of soluble VEGF receptor isoforms, circulating pterins and VEGF system SNPs as prognostic biomarkers in patients with acute coronary syndromes

Background

Development of collateral circulation in coronary artery disease is cardio-protective. A key process in forming new blood vessels is attraction to occluded arteries of monocytes with their subsequent activation as macrophages. In patients from a prospectively recruited post-acute coronary syndromes cohort we investigated the prognostic performance of three products of activated macrophages, soluble vascular endothelial growth factor (VEGF) receptors (sFlt-1 and sKDR) and pterins, alongside genetic variants in VEGF receptor genes, VEGFR-1 and VEGFR-2.

Methods

Baseline levels of sFlt-1 (VEGFR1), sKDR (VEGFR2) and pterins were measured in plasma samples from subgroups (n = 513; 211; 144, respectively) of the Coronary Disease Cohort Study (CDCS, n = 2067). DNA samples from the cohort were genotyped for polymorphisms from the VEGFR-1 gene SNPs (rs748252 n = 2027, rs9513070 n = 2048) and VEGFR-2 gene SNPs (rs2071559 n = 2050, rs2305948 n = 2066, rs1870377 n = 2042).

Results

At baseline, levels of sFlt-1 were significantly correlated with age, alcohol consumption, NTproBNP, BNP and other covariates relevant to cardiovascular pathophysiology. Total neopterin levels were associated with alcohol consumption at baseline. 7,8 dihydroneopterin was associated with BMI. The A allele of VEGFR-2 variant rs1870377 was associated with higher plasma sFlt-1 and lower levels of sKDR at baseline. Baseline plasma sFlt-1 was univariately associated with all cause mortality with (p < 0.001) and in a Cox’s proportional hazards regression model sFlt-1 and pterins were both associated with mortality independent of established predictors (p < 0.027).

Conclusions

sFlt-1 and pterins may have potential as prognostic biomarkers in acute coronary syndromes patients. Genetic markers from VEGF system genes warrant further investigation as markers of levels of VEGF system components in these patients.

Trial registration

Australian New Zealand Clinical Trials Registry. ACTRN12605000431628. 16 September 2005, Retrospectively registered.

Electronic supplementary material

The online version of this article (10.1186/s12872-018-0894-1) contains supplementary material, which is available to authorized users.

Genetic polymorphism rs6922269 in the MTHFD1L gene is associated with survival and baseline active vitamin B12 levels in post-acute coronary syndromes patients

Background and Aims

The methylene-tetrahydrofolate dehydrogenase (NADP+ dependent) 1-like (MTHFD1L) gene is involved in mitochondrial tetrahydrofolate metabolism. Polymorphisms in MTHFD1L, including rs6922269, have been implicated in risk for coronary artery disease (CAD). We investigated the association between rs6922269 and known metabolic risk factors and survival in two independent cohorts of coronary heart disease patients.

Methods and Results

DNA and plasma from 1940 patients with acute coronary syndromes were collected a median of 32 days after index hospital admission (Coronary Disease Cohort Study, CDCS). Samples from a validation cohort of 842 patients post-myocardial infarction (PMI) were taken 24–96 hours after hospitalization. DNA samples were genotyped for rs6922269, using a TaqMan assay. Homocysteine and active vitamin B12 were measured by immunoassay in baseline CDCS plasma samples, but not PMI plasma. All cause mortality was documented over follow-up of 4.1 (CDCS) and 8.8 (PMI) years, respectively. rs6922269 genotype frequencies were AA n = 135, 7.0%; GA n = 785, 40.5% and GG n = 1020, 52.5% in the CDCS and similar in the PMI cohort. CDCS patients with AA genotype for rs6922269 had lower levels of co-variate adjusted baseline plasma active vitamin B12 (p = 0.017) and poorer survival than patients with GG or GA genotype (mortality: AA 19.6%, GA 12.0%, GG 11.6%; p = 0.007). In multivariate analysis, rs6922269 genotype predicted survival, independent of established covariate predictors (p = 0.03). However the association between genotype and survival was not validated in the PMI cohort.

Conclusion

MTHFD1L rs6922269 genotype is associated with active vitamin B12 levels at baseline and may be a marker of prognostic risk in patients with established coronary heart disease.

Genetic variation in the renin-angiotensin-aldosterone system is associated with cardiovascular risk factors and early mortality in established coronary heart disease

This study examined renin-angiotensin-aldosterone (RAAS) system gene variants for associations with cardiovascular risk factors and outcomes in coronary heart disease. Coronary disease patients (n=1186) were genotyped for 21 single-nucleotide polymorphisms (SNPs) within angiotensinogen (AGT), angiotensin-converting enzyme (ACE), angiotensin-II type-1 receptor (AGTR1) and aldosterone synthase (CYP11B2). Associations with all-cause mortality and cardiovascular readmissions were assessed over a median of 3.0 years. The AGT M235T 'T' allele was associated with a younger age of clinical coronary disease onset (P=0.006), and the AGT rs2478545 minor allele was associated with lower circulating natriuretic peptides (P=0.0001-P=0.001) and E/E(1) (P=0.018). Minor alleles of AGT SNPs rs1926723 and rs11122576 were associated with more frequent history of renal disease (P0.04) and type-2 diabetes (P0.02), higher body mass index (P0.02) and greater mortality (P0.007). AGT rs11568054 minor allele carriers had more frequent history of renal disease (P=0.04) and higher plasma creatinine (P=0.033). AGT rs6687360 minor allele carriers exhibited worse survival (P=0.02). ACE rs4267385 was associated with older clinical coronary disease onset (P=0.008) and hypertension (P=0.013) onset, increased plasma creatinine (P=0.01), yet greater mortality (P=0.044). Less history of hypertension was observed with the AGTR1 rs12685977 minor allele (P=0.039). Genetic variation within the RAAS was associated with cardiovascular risk factors and accordingly poorer survival.

Association between endothelin type A receptor haplotypes and mortality in coronary heart disease

AIMS

The endothelin type A receptor, encoded by EDNRA, mediates the effects of endothelin-1 to promote vasoconstriction, vascular cell growth, adhesion, fibrosis and thrombosis. We investigated the association between EDNRA haplotype and cardiovascular outcomes in patients with coronary artery disease.

METHODS

Coronary disease patients (n = 1007) were genotyped for the His323His (rs5333) variant and one tag SNP from each of the major EDNRA haplotype blocks (rs6537484, rs1568136, rs5335 and rs10003447). EDNRA haplotype associations with clinical history, natriuretic peptides cardiac function and cardiovascular outcomes were tested over a median 3.8 years.

RESULTS

Univariate analysis identified a 'low-risk' EDNRA haplotype associated with later age of Type 2 diabetes onset (p = 0.004) smaller BMI (p = 0.021), and reduced mortality (log rank p = 0.001). Cox proportional hazards analysis including established cardiovascular risk factors revealed an independent association between haplotype and mortality (p < 0.0001).

CONCLUSION

These data highlight the potential importance of the endothelin system, and in particular EDNRA in coronary disease.

Genomic Risk Variants at 1p13.3, 1q41, and 3q22.3 Are Associated With Subsequent Cardiovascular Outcomes in Healthy Controls and in Established Coronary Artery Disease

Background—

Genome-wide association studies have identified gene variants associated with coronary artery disease risk; however, whether they affect disease progression is largely unknown. This study investigated associations between polymorphisms at 1p13.3 (rs599839), 1q41 (rs17465637), and 3q22.3 (rs9818870) and cardiovascular outcomes in healthy volunteers and in patients with established heart disease.

Methods and Results—

Canterbury Healthy Volunteer study (HV) (n=1649), Coronary Disease Cohort Study (CDCS) (n=1797), and Post-Myocardial Infarction study (PMI) (n=906) participants (New Zealand), were genotyped for rs599839, rs9818870, and rs17465637. Associations between genotype and anthropometric characteristics, neurohormonal analysis, echocardiography, and clinical outcomes over medium-long-term follow-up (median HV, 5.9 years; CDCS, 3.7 years; PMI, 11.3 years) were tested. At 1p13.3, HV and CDCS participants carrying 1 or more rs599839 G allele had a lower prevalence of dyslipidemia ( P ≤0.005) or lower levels of low-density lipoprotein ( P =0.031) and total ( P =0.004) cholesterol and/or less history of myocardial infarction ( P ≤0.04) compared with AA participants. Moreover, CDCS and PMI AG/GG participants had better cardiac function as indicated by echocardiography ( P ≤0.026), and fewer CDCS AG/GG participants were readmitted for a non-ST-segment elevation MI ( P =0.012) during follow-up. The polymorphism at 1q41 (rs17465637) was associated with better cardiovascular outcomes in the HV ( P =0.028) and PMI ( P =0.008) cohorts, and 3q22.3 (rs9818870) was a predictor of death/admission in the HV cohort ( P =0.045).

Conclusions—

These data suggest that coronary artery disease genomic risk variants at 1p13.3 and 1q41 are associated with subsequent clinical outcome in heart patients and confirm rs9818870 at 3q22.3 as a predictor of cardiovascular risk in individuals free of overt heart disease.

KCNE5 polymorphism rs697829 is associated with QT interval and survival in acute coronary syndromes patients

INTRODUCTION

The KCNE family is a group of small transmembrane channel proteins involved in potassium ion (K(+)) conductance. The X-linked KCNE5 gene encodes a regulator of the K(+) current mediated by the potassium channel KCNQ1. Polymorphisms in KCNE5 have been associated with altered cardiac electrophysiological properties in human studies. We investigated associations of the common rs697829 polymorphism from KCNE5 with baseline characteristics, baseline electrocardiographic (ECG) measurements, and patient survival in a cohort of post-acute coronary syndromes (ACS) patients (the Coronary Disease Cohort Study cohort).

METHODS AND RESULTS

DNA samples (n = 1,740) were genotyped for rs697829 using a TaqMan assay. Baseline ECG data revealed corrected QT (QTc) interval was associated with rs697829 in male, but not female, patients, being extended in the G genotype group (A 416 ± 1.71; G 431 ± 4.25 ms, P = 0.002). Covariate-adjusted survival was poorest in G genotype patients in Cox proportional hazard modeling of mortality data of males (P(overall) = 0.020). Male patients with G genotype had a hazard ratio of 1.44 (1.11-2.33) for death when compared to the A genotype male patients (P = 0.048) after adjustment for age, baseline log-transformed N-terminal pro-B-type natriuretic peptide (NTproBNP), β-blocker and insulin treatment, QTc interval, history of myocardial infarction, and physical activity score.

CONCLUSION

This study suggests an association between rs697829, a common single nucleotide polymorphism (SNP) from KCNE5, and ECG measurements and survival in postacute ACS patients. Prolonged subclinical QT interval may be a marker of adverse outcome in this group of patients. 

Association of genetic variation in the natriuretic peptide system with cardiovascular outcomes

Polymorphisms within individual natriuretic peptide genes have been associated with risk factors for cardiovascular disease, but their association with clinical outcomes was previously unknown. This study aimed to investigate the association between genetic variants in key genes of the natriuretic peptide system with cardiovascular outcomes in patients with coronary artery disease. Coronary disease patients (n=1810) were genotyped for polymorphisms within NPPA, NPPB, NPPC, NPR1 and NPR2. Clinical history, natriuretic peptide concentrations, echocardiography, all-cause mortality and cardiovascular hospital readmissions were recorded over a median 2.8 years. Minor alleles of NPPA rs5068, rs5065 and rs198358 were associated with less history of hypertension; minor alleles of NPPA rs5068 and rs198358 was also associated with higher circulating natriuretic peptide levels (p=0.003 to p=0.04). Minor alleles of NPPB rs198388, rs198389, and rs632793 were associated with higher circulating BNP and NT-proBNP (p=0.001 to p=0.03), and reduced E/E(1) (p=0.011), or LVESVI (p=0.001) and LVEDVI (p=0.004). Within NPPC, both rs11079028 and rs479651 were associated with higher NT-proBNP and CNP (p=0.01 to p=0.03), and rs479651 was associated with lower LVESVI (p=0.008) and LVEDVI (p=0.018). NPR2 rs10758325 was associated with smaller LVMI (p<0.02). A reduced rate of cardiovascular readmission was observed for minor alleles of NPPA rs5065 (p<0.0001), NPPB rs632793 (p<0.0001), rs198388 (p<0.0001), rs198389 (p<0.0001), and NPR2 rs10758325 (p<0.0001). There were no associations with all-cause mortality. In established cardiovascular disease, natriuretic peptide system polymorphisms were associated with natriuretic peptide levels, hypertension, echocardiographic indices and the incidence of hospital readmission for cardiovascular events.

A Common Variant at Chromosome 9P21.3 Is Associated With Age of Onset of Coronary Disease but Not Subsequent Mortality

Background—

Chromosome 9p21.3 (chr9p21.3) recently was identified by several genome-wide association studies as the genomic region most strongly associated with the risk of coronary artery disease. Within the chr9p21.3 locus, the single-nucleotide polymorphism rs1333049 has been demonstrated to be most strongly associated with susceptibility to developing coronary artery disease. However, the effect of rs1333049 on clinical outcomes in patients with established coronary disease has yet to be determined.

Methods and Results—

Coronary Disease Cohort Study (CDCS) (n=1054) and Post-Myocardial Infarction (PMI) (n=816) study participants were genotyped for rs1333049. Clinical history, circulating lipids, neurohormones, cardiac function, and discharge medications were documented. All-cause mortality and cardiovascular hospital readmissions were recorded over a median follow-up period of 4.0 years for the CDCS cohort and 9.1 years for the PMI cohort. The CDCS patients homozygous for the high-risk C allele had an age of onset 2 to 5 years earlier for coronary disease ( P =.005), angina ( P =.025), myocardial infarction ( P =.022), and percutaneous transluminal coronary angioplasty ( P =.009). Patients with the CC genotype also had higher levels of total cholesterol ( P =.033) and triglycerides ( P =.003). The PMI participants with the CC genotype were 3 years younger on admission ( P =.009). Cox proportional hazards analysis adjusting for established predictors of increased risk showed no significant association between rs1333049 genotype and mortality in either the CDCS ( P =.214) or the PMI ( P =.696) cohorts.

Conclusions—

The chr9p21.3 polymorphism rs1333049 was associated with an earlier age of disease onset in 2 coronary disease cohorts but not with poorer clinical outcome in either cohort.

The common G-866A polymorphism of the UCP2 gene and survival in diabetic patients following myocardial infarction

Background

A variant in the promoter of the human uncoupling protein 2 (UCP2) gene, the G-866A polymorphism, has been associated with future risk of coronary heart disease events, in those devoid of traditional risk factors and in those suffering from diabetes. We thus examined the impact of the G-866A polymorphism on 5-year survival in a cohort of 901 post-myocardial infarction patients, and the impact of type-2 diabetes on this relationship. The association of UCP2 with baseline biochemical and hormonal measurements, including levels of the inflammatory marker myeloperoxidase, was also examined.

Methods

UCP2 G-866A genotypes were determined using a polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) protocol. Myeloperoxidase levels were measured in plasma samples taken from 419 cohort patients 24–96 hours after admission.

Results

Genotypes were obtained for 901 patients with genotype frequencies AA 15.5%, GA 45.5%, and GG 39.0%. Genotype was not associated with survival in the overall cohort (mortality: AA 15.6%, GA 16.8%, GG 19.4%, p = 0.541). However, amongst diabetics, AA and GA genotype groups had significantly worse survival than GG diabetic patients (p < 0.05) with an attributable risk of 23.3% and 18.7% for those of AA and GA genotype respectively. Multivariate analysis using a Cox proportional hazards model confirmed that the interaction of diabetes with genotype was significantly predictive of survival (p = 0.031). In the cohort's diabetic subgroup AA/GA patients had higher myeloperoxidase levels than their GG counterparts (GA/AA, n = 51, 63.9 ± 5.23; GG, n = 34, 49.1 ± 3.72 ng/ml, p = 0.041). Further analysis showed that this phenomenon was confined to male patients (GA/AA, n = 36, 64.3 ± 6.23; GG, n = 29, 44.9 ± 3.72 ng/ml, p = 0.015).

Conclusion

Diabetic patients in this post-myocardial infarction cohort with UCP2 -866 AA/GA genotype have poorer survival and higher myeloperoxidase levels than their GG counterparts.

Angiotensin-converting enzyme 2 A1075G polymorphism is associated with survival in an acute coronary syndromes cohort

BACKGROUND

Polymorphisms of the angiotensin-converting enzyme 2 (ACE2) gene, which is located on the X chromosome, have been associated with hypertension and left ventricular hypertrophy in previous studies. We tested the hypothesis that the rare allele of an ACE2 gene polymorphism was associated with risk factors for and adverse outcome after acute coronary syndrome (ACS) events.

METHODS

Patients (n = 1,042) were recruited after admission for an ACS event and were genotyped for the A1075G polymorphism of the angiotensin-converting enzyme 2 gene. This genetic marker was tested for association with baseline measurements, echocardiographic measurements, and clinical outcome, over a median 2.19 years follow-up. As the ACE2 gene is X-linked, analyses were performed separately for males and females. Patients were predominantly of European ethnicity (90.1%).

RESULTS

The A1075 allele was significantly associated with covariate-adjusted mortality in male patients (hazard ratio 1.95, 95% CI 1.10-3.46, P = .047) but not unadjusted (hazard ratio 1.14, 95% CI 0.736-1.76, P = .56). The G1075 (P < .035) allele was more frequent in patients of Maori compared to European ancestry. E/E', an echocardiographic index of left ventricular diastolic function and filling pressure, was higher in males in the A1075 group (G allele group 10.5 [95% CI 10.0-11.0], A allele group 11.4 [95% CI 10.8-12.1], P = .024). A1075 genotype was significantly associated with male survival in the absence of (mortality: A 12.8%, n = 39; G 29.2%, n = 48; P = .037) but not in the presence of beta-blocker treatment (mortality: A 13.5% n = 273; G 8.2% n = 304, P = nonsignificant).

CONCLUSIONS

The A1075 allele was associated with covariate-adjusted mortality in male patients.

Angiotensinogen M235T and T174M Gene Polymorphisms in Combination Doubles the Risk of Mortality in Heart Failure

Angiotensinogen M235T and T174M polymorphisms have individually been associated with elevated levels of plasma angiotensinogen, hypertension, and left ventricular hypertrophy. In this study, heart failure patients (n=451) were genotyped for the angiotensinogen M235T and T174M polymorphisms to investigate association with survival (recorded over 4 years of follow-up) and prognostic hormone markers. Patients carrying the 235TT genotype (n=86) were 3 years younger at admission ( P =0.011), and, in those with hypertension, diagnosis was made ≈10 years earlier than other patients. Patients carrying ≥1 174M allele (n=94) were more likely to have a previous history of heart failure ( P =0.044) and increased mortality during follow-up (risk ratio: 1.69, 95% CI: 1.03 to 2.79; P =0.038) compared with 174TT homozygotes (n=355), despite having a higher left ventricular ejection fraction ( P =0.009). “High-risk” genotype combinations (defined a priori as 235TT and/or ≥1 174M allele; n=144; 32%) were independently predictive of mortality, conferring a 2-fold greater risk of dying during the follow-up period (odds ratio: 2.0; 95% CI: 1.3 to 3.0; P =0.001). This study suggested that angiotensinogen gene variants M235T and T174M may provide prognostic information for long-term survival in heart failure patients.

Evaluation of AMPD1 C34T genotype as a predictor of mortality in heart failure and post-myocardial infarction patients

BACKGROUND

The AMPD1 gene C34T polymorphism has previously been associated with prolonged survival in small cohorts of heart failure (HF) and coronary artery disease patients. This study aimed to corroborate the association of the AMPD1 C34T polymorphism with survival in larger myocardial infarction (MI) and HF cohorts.

METHODS

Genotypes were obtained for 935 post-MI (PMI) and 433 patients with established HF, with median follow-up times of 5.4 and 3.1 years, respectively. At admission, cardiac function was assessed by nuclear ventriculography (PMI) and echocardiography (HF) and plasma cardiac neurohormones were assayed.

RESULTS

Differences in mortality by AMPD1 genotype did not achieve significance, either for the overall HF (P = .07) or the overall PMI group (P = .28), but AMPD1 genotype predicted mortality in patients of both cohorts with a history of MI (HxMI). In contrast to previous studies, the mutant T allele was associated with poorer outcome. Mortality in HF HxMI patients was significantly different between genotype groups (n = 144, mortality CC 56.5%, CT/TT 77.8%, P = .027), but not in patients without HxMI. In PMI patients, the association of genotype with survival in the HxMI subgroup trended toward significance (n = 147, mortality CC 29.8%, CT/TT 45.5%, P = .093). Multivariate analysis of combined PMI and HF cohorts showed that HxMI patients with CT/TT genotype were at greater risk than all other groups (P < .001).

CONCLUSION

This study suggests that AMPD1 C34T genotype is not a predictor of survival in heart disease patients, except possibly those with HxMI.

Tumour targeting of humanised cross-linked divalent-Fab' antibody fragments: a clinical phase I/II study

Antibody engineering has made it possible to design antibodies with optimal characteristics for delivery of radionuclides for tumour imaging and therapy. A humanised divalent-Fab' cross-linked with a bis-maleimide linker referred to as humanised divalent-Fab' maleimide was produced as a result of this design process. It is a humanised divalent antibody with no Fc, which can be produced in bacteria and has enhanced stability compared with F(ab')(2). Here we describe a clinical study in patients with colorectal cancer using humanised divalent-Fab' maleimide generated from the anti-carcinoembryonic antigen antibody A5B7 radiolabelled with iodine-131. Ten patients received an i.v. injection of iodine-131-labelled A5B7 humanised divalent-Fab' maleimide, and positive tumour images were obtained by gamma camera imaging in eight patients with known lesions, and one previously undetected lesion was identified. True negative results were obtained in two patients without tumour. Area under the curve analysis of serial blood gamma counting and gamma camera images showed a higher tumour to blood ratio compared to A5B7 mF(ab')(2) used previously in the clinic, implying this new molecule may be superior for radioimmunotherapy. MIRD dose calculations showed a relatively high radiation dose to the kidney, which may limit the amount of activity that could be administered in radioimmunotherapy. However the reduction in immunogenicity was also a major advantage for A5B7 humanised divalent-Fab' maleimide over murine versions of this antibody suggesting that humanised divalent-Fab' maleimide should be a useful vehicle for repeated therapies.

Comparative expressed sequence hybridization to chromosomes for tumor classification and identification of genomic regions of differential gene expression

Altered expression of genes can have phenotypic consequences in cancer development and treatment, developmental abnormalities, and differentiation processes. Here we describe a rapid approach, termed comparative expressed sequence hybridization (CESH), which gives a genome-wide view of relative expression patterns within tissues according to chromosomal location. No prior knowledge of genes or cloning is required, and minimal amounts of tissue can be used. Expression profiles are achieved in a manner similar to the identification of chromosomal imbalances by comparative genomic hybridization analysis. The approach is demonstrated to indicate a chromosomal region that harbors overexpressed genes that may be associated with a drug-resistant phenotype. In addition, known and new regions of differential gene expression in both normal tissues and tumor samples from the soft tissue sarcoma group of rhabdomyosarcoma (RMS) are indicated. These regions included 2p24; overexpression of MYCN at 2p24 was confirmed by quantitative reverse transcription-PCR for all of the alveolar RMS cases and did not necessarily correspond to genomic amplification. Evidence including region specific microarray analysis indicated that overexpression of several genes from a region may be required for detection by CESH. This evidence is consistent with clusters of functionally related genes and mechanisms that affect the expression of a number of genes at a particular genomic location. The distinctive CESH profiles demonstrated in different subtypes of RMS show potential for tumor classification.

A novel, orally administered nucleoside analogue, OGT 719, inhibits the liver invasive growth of a human colorectal tumor, C170HM2

OGT 719 is a novel p.o. bioavailable nucleoside analogue in which galactose is incorporated onto the fluoropyrimidine moiety of the cytotoxic agent 5-fluorouracil (5-FU). OGT 719 has been designed to reduce the systemic toxicity normally associated with 5-FU while retaining activity against disease localized in the liver, in which it may be preferentially localized through the asialoglycoprotein receptor (ASGP-R). We report studies confirming the activity of OGT 719 in inhibiting growth of metastatic human colorectal tumors in the liver of nude mice. The human colorectal cancer cell line C170HM2 readily forms liver metastases in vivo. Oral administration of 1500 mg/kg/day OGT 719 inhibited liver tumor burden by 95% compared with vehicle control, without any observable signs of toxicity. When the tumor burden was increased and the same OGT 719 treatment was compared with a standard clinical dose regimen of 25 mg/kg/day 5-FU/leucovorin given i.v., both treatments were equally efficacious, although 5-FU/leucovorin treatment started 7 days earlier. In contrast to 5-FU, OGT 719 is p.o. bioavailable and has a plasma half-life between 1.5 and 3 h. Several colorectal cancer cell lines express the asialoglycoprotein receptor, although no significant levels can be detected in C170HM2 cells, consistent with the observation that OGT 719 is approximately 3 log orders of magnitude less potent in vitro than 5-FU. Flux through thymidylate synthase, as measured by 3H release from [3H]dUrd, was inhibited by OGT 719 at 4 h. The notable difference in the potency of OGT 719 efficacy on C170HM2 cells in vitro and in vivo supports our model of liver-specific activation of OGT 719. As our data suggest, OGT 719 may significantly inhibit growth of metastatic colorectal tumors in the liver in vivo. This hypothesis is presently being explored in clinical trials for primary hepatocellular carcinoma and colorectal liver metastases.

Late results of surveillance of clinical stage I nonseminoma germ cell testicular tumours: 17 years' experience in a national study in New Zealand

OBJECTIVE

To re-evaluate a national prospective study in New Zealand after 17 years to define whether orchidectomy alone and surveillance for nonseminoma germ cell testicular tumour (NSGCTT) is a sound policy and matches the results achieved by other treatment protocols.

PATIENTS AND METHODS

Between 1980 and 1997, 248 men with stage I NSGCTT, from six New Zealand centres, were managed by orchidectomy alone and surveillance, with treatment of relapses using combination chemotherapy.

RESULTS

Seventy of the 248 patients (28%) relapsed; 42 of 92 (46%) with vascular and/or lymphatic invasion (VLI) in the primary tumour relapsed, whereas only 26 of 151 (17%) without this feature relapsed (P<0.001). VLI was the only identifiable risk factor for relapse in this series. Only one relapse occurred >28 months after orchidectomy. Despite poor compliance in some patients (12%) their survival was not prejudiced. Three patients died from disease despite chemotherapy at relapse. At 17 years and a median follow-up of 53 months, 242 of the 248 men are disease-free and the disease-specific survival rate is 98%.

CONCLUSIONS

This study shows that orchidectomy alone and treatment of relapses produces excellent long-term results without the adverse effects associated with retroperitoneal node dissection or elective chemotherapy for high-risk cases.

Use of body mass index to monitor treatment of obese adolescents

PURPOSE

Absolute weight loss may not always be the best measure of adherence and response to therapy in obese adolescents if weight gain owing to linear growth is not considered. We wished to compare short-term absolute weight and height changes with changes in body mass index (BMI) in a group of severely obese adolescents to determine the most meaningful measure of treatment response.

METHODS

We analyzed weight, height, and BMI in 27 adolescents, 10-18 years of age, referred for management of severe obesity. Subjects attended clinic on at least three occasions within a 6-24-month period. Detailed profiles of usual daily food intakes, physical activities, and family and environmental structure/activities were obtained, and specific goals to achieve weight control were negotiated with adolescents and their families at each visit. Weight, height, and BMI at the initial visit and at the most recent visit were compared.

RESULTS

While 48% of our population actually lost weight, 78% either had no change or a decrease in BMI during the observation period. Differences between initial and most recent heights and BMIs were statistically significant, but weight changes were not significant.

CONCLUSIONS

In addition to weight, BMI should be routinely used and reported when monitoring the response to specific interventions in growing adolescents. Evaluation of weight alone may underestimate the adolescent's adherence to treatment goals.

Bilateral germ cell testicular tumors in New Zealand: experience in Auckland and Christchurch 1978-1994

PURPOSE

The incidence of germ cell testicular tumors (GCTTs) is increasing world wide, and with effective treatment, the majority of patients are being cured. Thus, the clinical and social impact of a second testicular tumor is becoming more important. The frequency, cumulative risk, and relative risk of developing a second testicular cancer in New Zealand have been documented and compared with other reports.

PATIENTS AND METHODS

The records of 741 men presenting with germ cell testicular cancer in Auckland and Christchurch between 1978 and 1994 have been reviewed, and these data have been compared with data from other published studies. Cumulative risk was assessed by the Kaplan-Meier method.

RESULTS

Over 2% of the study population developed a second germ cell testicular cancer. The cumulative risk was 5.2% over 15 years. The relative risk of developing a contralateral testicular tumor is 27.5 times higher than age-matched New Zealand peers. These results match the only comparable report in the literature. Five of the 16 bilateral tumors (31%) were synchronous, which is a higher incidence than in any other reported series. There was no concordance of histology in the first and second tumors. Prior exposure to cisplatin combination chemotherapy did not prevent the development of a second tumor.

CONCLUSION

Men who are cured of a germ cell testicular cancer have a greatly increased risk of developing a second testicular cancer. Such patients should be informed of this risk and ideally kept under long-term surveillance.

Effect of hammerhead ribozyme against human thymidylate synthase on the cytotoxicity of thymidylate synthase inhibitors

One of the resistance mechanisms to folate-based thymidylate synthase (TS) inhibitors is the increase in TS activity in tumor cells. Human B lymphoblastoid cell line (W1L2) was made resistant to a lipophilic non-polyglutamatable TS inhibitor (ZM249148), and the subline (W1L2:R179) showed a 20-fold increase in TS enzyme activity with concomitant overexpression of TS mRNA. To overcome the resistance, we designed a ribozyme that can cleave the CUC sequences in a triple tandemly repeated sequence of TS mRNA. Expression of this ribozyme in W1L2:R179 cells transfected with Epstein Barr virus-based expression vector resulted in sensitization to TS inhibitors concomitantly with a decrease of TS expression. The ribozyme expressed in transfectants was shown to be functional in cleaving artificial TS RNA in vitro.

Results of the surveillance policy of stage I non-seminomatous germ cell testicular tumours

A series of 115 patients with clinical Stage I non-seminomatous germ cell testicular tumours were managed with orchiectomy and close surveillance (median follow-up 36 months, range 3-119); 34 (29.5%) relapsed, 21 within 6 months, 29 within a year and the latest at 28 months. At relapse all patients were treated with platinum or analogue-based drug combinations, supplemented in 7 by retroperitoneal node dissection; 30 patients achieved durable remissions and 2 have had further relapses successfully treated. Two died; both had malignant teratoma intermediate with primary stage T1 and vascular and/or lymphatic invasion of primary tumour. At a median follow-up time of 36 months, the survivors (98.3%) demonstrate no evidence of disease, these results matching the outcome of other methods of management. Vascular and/or lymphatic invasion was associated with an enhanced relapse rate but specific histology, T stage of the primary and pre-orchiectomy serum alpha-fetoprotein status did not appear to favour relapse. The first sign of relapse was tumour marker alone in 10 patients, radiological features alone in 12, or both in 10 patients. However, in 2 cases the relapse was first detected clinically. Furthermore, pre-orchiectomy and relapse marker status did not correlate well. These points emphasise the importance of all aspects of follow-up, none of which can be safely omitted.