Acne vulgaris is a chronic inflammatory disease of pilosebaceous units causing comedones, papules,pustules, nodules, and possibly scaring on the face, chest and upper back. It affects virtually all adolescents, to varying degrees of severity, and usually appears at the time of puberty.
Pathogenesis of AV is multifactorial and involves many pathways including; hormonally-mediated sebum overproduction, follicular hyperkeratinization , and chronic inflammation of the pilosebaceous units . Microbes, genetic susceptibilities and various environmental factors have been linked to pathogenesis of the condition.
Although the pathogenesis of acne involves many factors, a number of studies indicate that oxidative stress is one of the major factors . It has been reported that oxygen free radicals, which are generated by the neutrophils on the follicular wall to kill microorganisms, may cause cell damage at the site of inflammation. Sebum composition is altered in acne and ROS produced by neutrophils are involved in the irritation and destruction of the follicular wall that is responsible for the inflammatory progression of acne .
Angiotensin converting enzyme (ACE) is an enzyme that can convert angiotensin-1 to angiotensin-II , which is a potent vasoconstrictor , and inactivate the vasodilator bradykinin . Angiotensin II increases generation of ROS ,creating an oxidative stress state . ACE plays an important role in circulatory hoemostasis and inflammation.
ACE is expressed in vascular endothelial cells , skin cells and immune system cells . An insertion deletion (I/D) polymorphism of 287 base pair repetitive sequence in intron 16 of the ACE gene affects ACE activites. ACE I/D gene polymorphism have been reported in different ethinic groups in different diseases. The relation between ACE gene polymorphism in many skin diseases with oxidative stress had been investigated as vitiligo & psoriasis.
The aim of this study was to investigate the association between ACE gene insertion / deletion polymorphism , and risk of AV among Egyptian patients.
This study included 50 patients suffering from acne vulgaris (Patients group) and 30 apparently healthy individuals of matched age and sex as a control group (Control group). According to Global Acne Grading System , the patients were classified into mild (16 patients) , moderate (18 patients) and severe (16 patients). The ACE I/D polymorphism was detected by PCR in all patients and control groups.
The results of this study showed that no statistically significant difference was found between patients and control groups regarding age or gender . Regarding the clinical picture of the patient group , the disease is more common in females . Majority of AV patients had gradual onset, and progressive course . Face is affected in all cases.
Regarding the relation between ACE I/D gene polymorphism and AV , our study showed that there was statistically significant difference between AV patients and control group regarding ACE genotypes with DD genotype more common in patients than in control group . Also the results showed that D allele is more common in AV patients than the control group , and the difference was statistically significant .
Regarding demographic characters no statistically significant difference was found between ACE genotypes frequency and age or gender of the patients. Also insignificant difference was obtained with onset of the disease and course of the disease .
Statistically insignificant difference was also detected between ACE genotypes frequency and the following clinical parameters : with severity of the disease ( p = 0.15 ) , with presence of scar ( P = 0.48 ),with smoking ( p = 0.28 ) , with diet ( P= 057) , with sun exposure ( p = 0.41) , and with psychological stress (0.592).
Statistically significant difference was detected in our study between ACE genotypes frequency and family history, but insignificant difference was detected with other risk factors such as severity of the disease , presence of scar , smoking , diet, exposure to sun and psychological stress
Logistic regression analysis was conducted on our results for prediction of more severe grade within all studied patients, applying age, sex, smoking, sun exposure, diet, stress as covariates. None of them was considered as independent risk factor for higher degree of severity in studied acne patients in univariate and multivariate analysis.
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