Angiotensin-converting enzyme gene insertion/deletion polymorphism frequency in normotensive children with a positive family history of essential hypertension

Hypertension in 172 Chinese Children: An 8-Year Retrospective Study

BACKGROUND

We evaluated children with hypertension and compared those with essential and secondary (including renal and non-renal) hypertension.

METHODS

This retrospective study analyzed data from hypertensive children (age, 0-18 years) referred for treatment between January 2008 and December 2015. Demographic factors, causative factors, and medical treatments were evaluated. Treatment failure was defined as a systolic or diastolic blood pressure ≥95th percentile for age, gender, and height on three separate occasions, despite treatment. All patients not meeting the failure criteria were considered to have controlled hypertension. The control rate was defined as the proportion of patients with controlled blood pressure.

RESULTS

Among 172 consecutive patients, 28% had essential hypertension and 72% had secondary hypertension. As compared with children with secondary hypertension, those with essential hypertension had a higher frequency of family history of hypertension (P<0.001), a higher body mass index (BMI) (P=0.001), lower frequency of proteinuria (P=0.003), lower uric acid (P=0.04), and lower triglyceride (P=0.048). The medications used in the controlled group were similar to those used in the uncontrolled group. Angiotensin-converting enzyme inhibitors (ACEIs) were only used in nephrogenic patients, and a higher rate of ACEI use seemed to increase control rates. Control rates did not significantly differ by age, number of drugs, or cause of hypertension.

CONCLUSIONS

As compared with children with secondary hypertension, those with essential hypertension were more likely to have a family history of hypertension and had a higher BMI, lower frequency of proteinuria, and lower uric acid and triglyceride concentrations. Treatment guidelines for essential and secondary hypertension should be established for children of all ages.

Factors Associated with Primary Hypertension in Pediatric Patients: An Up-to-Date

BACKGROUND

Arterial hypertension in children is considered a common alteration nowadays, mainly because obesity is a growing worldwide problem closely related to increased blood pressure. Childhood hypertension can be classified as primary or secondary, depending on the etiology. Primary or essential hypertension still has its pathophysiology not fully elucidated, and there is no consensus in the literature on most underlying mechanisms. In this review, genetic and environmental factors, including sodium and potassium intake, socioeconomic status, ethnicity, family structure, obesity, sedentary lifestyle, prematurity and low birth weight, prenatal and postnatal exposures are highlighted.

OBJECTIVE

The present study aimed to perform an update on primary hypertension in childhood, providing clinicians and researchers an overview of the current state of the literature regarding the influence of genetic and environmental factors.

METHODS

This integrative review searched for articles on genetic and environmental factors related to primary hypertension in pediatric patients. The databases evaluated were PubMed and Scopus.

RESULTS

The studies have provided insights regarding many genetic and environmental factors, in addition to their association with the pathophysiology of primary hypertension in childhood. Findings corroborated the idea that primary hypertension is a multifactorial disease. Further studies in the pediatric population are needed to elucidate the underlying mechanisms.

CONCLUSION

The study of primary hypertension in pediatrics has utmost importance for the adoption of preventive measures and the development of more efficient treatments, therefore reducing childhood morbidity and the incidence of cardiovascular diseases and other health consequences later in life.

The drop that spilled the cup: acute myocardial infarction in a young woman with underlying thrombophilic polymorphisms and oral contraceptive use

We present the case of a 28-year-old woman who was admitted to our cardiology unit for acute coronary syndrome. Her history was notable for cardiovascular disease familiarity, active smoking, and oral contraceptive use. On further analysis, she was noted to have thrombophilic polymorphisms involving the plasminogen activator inhibitor (PAI), angiotensin-converting enzyme (ACE), and methylenetetrahydrofolate reductase (MTHFR) genes. We discuss the implications that these cofactors may have had in the genesis of the disease.

Angiotensin converting enzyme insertion/deletion polymorphism is associated with increased adiposity and blood pressure in obese children and adolescents

BACKGROUND

The insertion/deletion polymorphism in the gene encoding the angiotensin-converting enzyme (ACE I/D) was associated with arterial hypertension and obesity in adults, but the data in children are scarce and yielded contrasting results. We assessed the impact of the ACE I/D on blood pressure and obesity related traits in a Brazilian cohort of obese children and adolescents.

METHODS AND RESULTS

ACE I/D was genotyped in 320 obese children and adolescents (64% of girls) aged 7-16years, referred for a weight-loss program. We observed an association of the D-allele with blood pressure and with pre-hypertension/hypertension in boys (odds ratio 2.44, 95% C.I. 1.34-4.68, p=0.005 for a codominant model). The D-allele, insulin resistance and body fat mass had independent and additive effects and explained 14% of the variance of pre-hypertension/hypertension. The BMI, waist circumference, and body fat mass were significantly higher in DD/ID boys than in II boys (p<0.005). Allelic associations with obesity related traits were independent of the association with blood pressure. No genotype associations were observed in girls.

CONCLUSIONS

The D-allele of the ACE I/D polymorphism was associated with arterial hypertension and with obesity related traits in boys, but not in girls, in a cohort of obese children and adolescents. These associations were independent of each other, as well as of the effects of other confounding traits such as insulin secretion, insulin sensitivity and glucose tolerance. Our results are in agreement with experimental evidences suggesting that the renin-angiotensin system plays a role in the regulation of visceral adipose tissue accumulation.

Association of ACE gene insertion/deletion polymorphism with birth weight, blood pressure levels, and ACE activity in healthy children

BACKGROUND

The human angiotensin-converting enzyme (ACE) gene contains a polymorphism consisting of either an insertion (I) or a deletion (D) of a 287 bp Alu repetitive sequence in intron 16. The potential role of ACE polymorphism in the risk of developing hypertension or other cardiovascular disorders has not been determined in relation to birth weight (BW).

METHODS

The ACE genotype and plasma ACE activity were determined in 167 children. Among these children, 60 were identified with low BW (LBW), and 107 were of normal BW (NBW).

RESULTS

ACE activity levels were significantly elevated in LBW children compared with the NBW group (P < 0.001). There was a significant association of the ACE activity with systolic blood pressure (SBP) levels in our population (P < 0.001). Among the ACE genotypes, no significant differences were found with respect to BW (P = 0.136). However, our results revealed that LBW children had a higher D allele frequency than NBW children (P = 0.036). When analyzed by quartiles of SBP or ACE activity, we found a greater frequency of both the LBW children and those carrying the DD genotype in the highest quartiles of these parameters, whereas the NBW children tended to be in the lowest quartile (P < 0.001). Similar results were observed with the heterozygote ID children after categorization by quartiles of both SBP (P < 0.001) and ACE activity (P = 0.004).

CONCLUSIONS

The ACE I/D polymorphism, especially the DD genotype, can be interpreted as a major factor in association between LBW and high BP levels.