Angiotensin-converting enzyme genotype may predict survival following major trauma.

BACKGROUND: As a key component of the endocrine renin-angiotensin system (RAS), angiotensin-converting enzyme (ACE) regulates circulatory homeostasis. Meanwhile, the local RAS influences tissue growth, inflammatory and metabolic responses. The absence (deletion, D) rather than the presence (insertion, I) of a 287 base pair fragment in the ACE gene is associated with higher circulating and tissue ACE activity, with excess mortality in critical illness (including adult acute respiratory distress syndrome and paediatric meningococcal infection) and with worse functional outcome from traumatic brain injury. OBJECTIVE: To determine if the ACE genotype is associated with mortality following major trauma. METHODS: 41 subjects with major trauma admitted to the Royal London Hospital over a 2-year period via the Helicopter Emergency Medical Service were enrolled. ACE genotype was available in 36. Injury Severity Score (ISS), Revised Trauma Score (RTS), age, sex and outcome data were recorded for each. ACE genotype was determined from leucocyte DNA using well described techniques. RESULTS: The presence of one or more D alleles was associated with a mortality of 36.4% compared with 7.1% for II alleles (p = 0.048). Age (p = 0.044) also predicted mortality whereas RTS (p = 0.08) and ISS (p = 0.46) did not. ACE genotype was significantly associated with RTS but not age or ISS. CONCLUSION: The ACE D allele may be associated with mortality from major trauma. Replication of these findings in larger studies may aid definition of high-risk subgroups that would benefit from early intensive management. New therapeutic targets might also be suggested.

Left ventricular growth response to exercise and cigarette smoking: data from LARGE Heart.

BACKGROUND: Increasing left ventricular mass is a risk factor for cardiovascular morbidity and mortality. OBJECTIVE: To examine the possible association of smoking with the left ventricular growth response in men. METHODS: Left ventricular mass was measured in 309 army recruits before and after an identical 12-week physical training programme. Left ventricular mass was determined using cardiovascular magnetic resonance. RESULTS: Left ventricular mass increased with training (mean (standard deviation (SD)) 3.83 (10.81) g, p<0.001). By univariate analysis, exercise-induced change in left ventricular mass was positively associated with cigarette smoking (mean (SD) 1.69 (11.10) g v 4.76 (10.23) g for non-smokers v ex- and current smokers, respectively; p = 0.026), whereas age, height, diastolic and systolic blood pressure (SBP), alcohol consumption or indices of physical activity were not significantly associated with change in left ventricular mass. Multivariate analysis showed body weight, smoking status and SBP to be independent predictors of left ventricular mass (incremental R(2) = 3.4%, p = 0.004; R(2) = 4.9%, p = 0.024; and R(2) = 1.7%, p = 0.041, respectively). CONCLUSIONS: Cigarette smoking and SBP are associated with exercise-induced left ventricular growth in young men. The positive association of smoking with changes in left ventricular mass is surprising, given the limited exposure of these subjects to smoking, and although these data do not prove causation, they are of great interest to those trying to uncover the drivers of left ventricular hypertrophy, as well as to those examining the possible ill-effects of smoking in the young.

Performance at altitude and angiotensin I-converting enzyme genotype.

The "insertion" (I) rather than "deletion" (D) variant of the human angiotensin-converting enzyme (ACE) gene is associated with both lower tissue ACE activity and elite performance at high altitude. We examined whether the onset of acute mountain sickness (AMS), and further performance on reaching the summit of Mt. Blanc are influenced by the ACE I/D polymorphism. Two hundred and eighty-four climbers (235 males, [37.0 (11.0 years], (86 DD, 142 ID, 56 II)) had assessment of their AMS status upon arrival to the Gouter hut (3,807 m) on day 1, and again on day 2 after an attempted ascent to the summit of Mt. Blanc (4,807 m). Success in reaching the summit was genotype dependent (87.7% of DD, 94.9% of ID and 100% of II individuals; P=0.048); I allele frequency for those reaching the summit was 0.47 compared to 0.21 for those who did not (P=0.01). The onset of AMS on day 1 appeared to be dependent on genotype (P=0.003), but with those heterozygous being less affected. ACE genotype was not associated either with AMS onset or severity on day 2. Thus, ACE I/D genotype is associated with successful high altitude ascent in this prospective study-an association not explicable by genotype-dependence of AMS onset or severity. Values are given as mean (SD) unless otherwise stated.