Evaluating Serum Elastin Levels in Striae Gravidarum Stria

Turk J Biochem 2020; 45(1): 76–82

Research Article

Beril Gürlek, Ülkü Mete Ural, Sibel Tuğcugil, Medeni Arpa* and Özgür Önal Evaluating serum elastin levels in striae gravidarum Stria gravidarumda serum elastin düzeylerinin değerlendirilmesi https://doi.org/10.1515/tjb-2019-0050 Conclusions: Serum elastin levels were increased in Received February 10, 2019; accepted May 8, 2019; previously women with SG. However, the newly synthesized elas- published online July 26, 2019 tin may not be functional as it is thin and disorganized. Abstract Therefore, increased elastin production may not prevent the formation of striae. This finding may provide an impe- Objective: Striae gravidarum (SG) is the most common tus to explore the pathomechanisms of striae. Further dermatological defect in pregnancy leading to cosmetic controlled trials are warranted to determine the clinical anxiety with unknown etiopathogenesis. The aim of the significance of serum elastin levels in the formation of SG. study was to analyze the relation between serum elastin Keywords: Elastin; Cosmetic; Complication; Pregnancy; levels and striae and identify possible independent asso- Striae gravidarum. ciated risk factors. Materials and methods: This was a prospective observational study. In total, 138 primipara pregnant women Öz were examined before delivery. Participants were separated into two groups according to the presence of SG. Amaç: Stria gravidarum, gebelikte kozmetik kaygıya yol Striae assessment was performed according to Davey açan en yaygın dermatolojik sorunlardan biridir. Çalış- score. Before the active phase of labor patients were mamızın amacı, serum elastin düzeyleri ile stria gelişimi physically examined and blood samples were collected. arasındaki ilişkiyi araştırmak ve stria gravidarumun Personal characteristics, features of birth, skin find- oluşumunda rol alan risk faktörlerini belirlemektir. ings and serum elastin levels were compared between Gereç ve Yöntem: Prospektif olarak planlanan bu çalışma, groups. doğum öncesi kliniğimize başvuran 138 primipar gebe Results: Term pregnant women with SG had signifi- katılımcı ile yapıldı. Katılımcılar, stria gravidarum varlı- cantly higher serum elastin levels than those without SG ğına göre iki gruba ayrıldı. Stria değerlendirmesi Davey (99.46 ± 32.92 vs. 88.36 ± 19.12, respectively; p = 0.018). skoruna göre yapıldı. Doğumun aktif fazından önce hasta- lara fizik muayene yapıldı ve kan örnekleri alındı. Gruplar *Corresponding author: Medeni Arpa, Recep Tayyip Erdoğan arasında klinik ve doğum özellikleri, cilt bulguları ve University School of Medicine, Department of Biochemistry, serum elastin düzeyleri karşılaştırıldı. Islampasa Mah., 53200 Rize, Turkey, Phone: +5424296721, Bulgular: Stria gravidarumu olan gebe kadınlarda stria Fax: +904642130493, e-mail: [email protected]. gravidarumu olmayanlara göre serum elastin düzey- https://orcid.org/0000-0001-8321-4829 leri anlamlı derecede yüksekti (sırasıyla 99.46 ± 32.92 ve Beril Gürlek and Ülkü Mete Ural: Recep Tayyip Erdoğan University School of Medicine, Department of Obstetrics and Gynecology, Rize, 88.36 ± 19.12; p: 0.018). Turkey, e-mail: [email protected] (B. Gürlek); Sonuç: Stria gravidarumu olan gebe kadınlarda serum [email protected] (Ü. M. Ural). https://orcid.org/0000- elastin düzeyleri artmaktadır. Bununla birlikte, yeni sen- 0001-6163-6756 (Ü. M. Ural) tezlenen elastin ince ve dağınık yapıda olduğu için fonk- Sibel Tuğcugil: Private Practice, Dermatology, Trabzon, Turkey, siyonel değildir. Bu nedenle, artan elastin üretimi, stria e-mail: [email protected] Özgür Önal: Süleyman Demirel University School of Medicine, oluşumunu önlemede etkili olmayabilir. Bu sonuç gebe- Department of Public Health, Isparta, Turkey, likte stria patomekanizmasının anlaşılmasında önemli e-mail: [email protected] bir veri olsa da elastinin striae gravidarum gelişimindeki Beril Gürlek et al.: Elastin levels and striae gravidarum 77 klinik önemini belirlemek için daha fazla çalışmaya Materials and methods ihtiyaç vardır. Anahtar Kelimeler: Elastin; gebelik; kozmetik; Study design komplikasyon; stria gravidarum. A total of 138 term pregnant women prior to the active phase of delivery who was admitted to the obstetrics and Introduction gynecology department of our tertiary care center were enrolled in this prospective observational cohort study. Striae gravidarum (SG) is considered to be the most Before the study, the permission of the local Ethics Com- common and disfiguring cutaneous complication of mittee was acquired (Protocol no: 2018/148). All partici- pregnancy. Prevalence of SG varies between 55 and 90%, pants were asked to sign consent forms. and SG typically appears in the second and third trimes- All participating women in this series were primi- ters [1]. SG occurs anywhere on the body, especially on parous women between 37 and 40 gestational weeks. the abdomen and breasts. The buttocks, thighs, axillae, Exclusion criterias were multiple pregnancies, post-term, legs, and hips are less commonly involved [2]. Lesions macrosomia, intrauterine growth restriction, gestational may vary in size and color, and the scars are typically hypertension, preeclampsia and polyhydramnios, known a few centimeters in length and 1–10 mm in width [3]. systemic diseases (diabetes mellitus, gestational hyper- Although SG does not cause serious medical problems, it tension, asthma, collagen tissue disease). Also, patients may lead to itchiness and restlessness during pregnancy. used drugs or any preventive cream or oil for SG and As affected areas may become itchy, scratching them ineligible to answer a questionnaire were excluded. Age, increases the risk of infection [4]. Over the long term, gestational week, presence of SG, week of onset for SG, disfiguring SG may cause psychological distress, lack smoking habit, daily fluid intake, skin type according of self-confidence and represent an important aesthetic to the Fitzpatrick classification [12], history of SG in the concern [5]. adolescence, history of SG in the mother or sister, weight The pathogenesis includes genetic and hormonal and body mass index (BMI; kg/m2) prior to pregnancy, factors as well as increased mechanical stress on con- abdominal (in centimeters, from the level of umbilicus), nective tissue [6]. Many risk factors have been studied for hip and thigh circumferences at admission, mode of their possible effect on the elasticity of the skin during delivery, birth weight and sex of the infant were recorded. pregnancy, including skin type and structure, race, family Striae on the abdominal region were scored with the history, skinfold thickness, birth weight of the newborn, Davey method [4]. Accordingly, the skin is divided into pre-preganancy body mass index (BMI), age, weight gain, four parts as upper left and right, lower left and right, impaired glucose tolerance, socioeconomic status, poor umbilicus being in the center. Each quadrant was scored nutrition, type of delivery, and even eye and hair color according to the presence and severity of striae and groups [5–7]. However, the precise underlying etiology of SG were formed according to the total score. Participants who remains unclear [2, 6, 7]. did not have striae were given zero points, those with mild Elastin is a scleroprotein that has a texture similar striae were given one point and those with severe striae to rubber but is 5 times more elastic. Extracellular were given two points. Participants were divided into two matrix assures the structural support of the skin, and main groups according to the presence of striae. Group elastin plays an important role in the extracellular 1 included patients with no striae and group 2 consists matrix. Alterations in elastin metabolism are included of patients with striae. Group 2 was divided into three in the pathophysiology of destructive lesions affecting subgroups according to the severity of striae, as mild (1–2 elastin-rich organs, such as blood vessels, kidney, skin, points), medium (3–6 points), and severe (7–8 points) and lungs. Serum elastin levels are increased in emphy- Fitzpatrick skin type classification [12] is a univer- sema, abdominal aortic aneurysm, and atherosclerosis sal system that has been used for years to classify peo- [8, 9]. Although recent studies have shown changes ple’s skin types. This classification method can be used in the structure of elastin in striae tissue in pregnant to investigate the effects of sunlight, laser, and drugs on women [10, 11], there are no studies investigating elastin different skin types. According to Fitzpatrick skin type concentration in serum samples. The aim of the study classification, skin types are divided into six categories. was to investigate the role of elastin in the etiopatho- A pale white skin which usually burns and does not tan genesis of SG. is classified as type 1, dark brown or black skin which 78 Beril Gürlek et al.: Elastin levels and striae gravidarum never burns and tans darkly is considered as type 6. In performed. A p-value <0.05 was considered statistically our study, we divided skin types into three groups. Type significant. A (Fitzpatrick skin type 1–2), type B (Fitzpatrick skin type 3–4), type C (Fitzpatrick skin type 5–6). Results

Anthropometric measurements Participants were separated into two groups due to the existence of the SG. The mean values were calculated Height and weight measurements of the patients were for each of the variables under investigation among the performed with the same weighing device which was groups. Comparisons of personal characteristics between calibrated once a week. BMI was calculated as weight pregnant women with and without SG are presented in (in kilograms) divided by height (in meters) squared Table 1. (kg/m2). Maternal thigh, hip, abdominal circumference Among 138 study participants, 105 (76.0%) had SG (cm), newborn head circumference (cm) and newborn (Group 2), and 33 (23.9%) did not develop SG (Group 1). weight (grams) were measured. Anthropometric measure- In Group 2, 32 had SG (30.4%) only in the abdomen; 15 ments were completed before delivery. (14.2%) had striae exclusively in other regions, such as hip, thigh, and breast; and 58 (55.2%) had SG in both abdominal and other regions. In the SG group, SG was Laboratory analysis developed most commonly after 20 weeks of pregnancy (80.0%). According to Davey scoring, the intensity of SG in Blood collection Group 2 was as follows: 32 (30.4%) were mild, 54 (51.4%) were moderate, and 19 (18.0%) were severe. Before the active phase of labor, blood samples were We found no significant differences between groups obtained from antecubital vein to the SST tubes (BD Vacu- regarding smoking habit and positive SG history in their tainer SST II Advance, USA). Eight milliliter of blood is family. In the SG group, the presence of acne during preg- collected from the patient and the control groups after nancy was remarkably more common in the group without an 8–12 h of fasting. Blood samples were centrifuged at SG (p = 0.023). The skin type (p = 0.001) was also a signifi- 1000 × g at 4°C for 10 min to obtain serum samples. Then cant factor in the development of SG (Table 1). SG was dra- serum samples were separated immediately and stored at matically higher in the Type C group compared with Type −20°C until elastin measurement.

Table 1: Comparison of personal characteristics between groups according to the presence or absence of striae gravidarum. Measurement of serum elastin levels Group 1 Group 2 p-Value Elastin levels were measured by commercially available (n = 33) (n = 105) sandwich ELISA with Human Elastin ELISA kit (Eastbiop- Smoking harm, China). The assay range is between 0.5 μg/mL and Yes 3 (50.0%) 3 (50.0%) 0.148 150 μg/mL, and the intraassay and interassay CVs were No 30 (22.7%) 102 (77.3%) <%10 and <%12, respectively, according to the manufac- Family history turer. The sensitivity of the assay was 0.251 μg/mL accord- Absent 18 (20.7%) 69 (79.3%) 0.246 ing to the manufacturer. Present 15 (29.4%) 36 (70.6%) Acne during pregnancy Absent 6 (12.5%) 42 (87.5%) 0.023 Statistical analysis Present 27 (30.0%) 63 (70.0%) Skin type Type A 15 (29.4%) 36 (70.6%) 0.001 SPSS software, version 25.0 (SPSS Inc., Chicago, IL, USA) Type B 15 (38.5%) 24 (61.5%) was used to analyze the collected data variables were Type C 3 (6.3%) 45 (93.8%) distributed homogenously into two groups. The level of Group 1, pregnant women without striae gravidarum; group 2, confidence was 95%. Equality of variances was checked pregnant women with striae gravidarum. Values are provided as the by the Levene test. Descriptive statistics, Student t-test, mean ± standard deviation. p < 0.05 indicates statistical significance Chi-square (χ2), and logistic regression analyses were and marked with bold. Beril Gürlek et al.: Elastin levels and striae gravidarum 79

A (p = 0.006) and Type B (p = 0.001), revealing statistical Comparisons of birth parameters between groups significance based on skin type. based on the presence or absence of SG are shown in Comparisons of variables between groups accord- Table 3. Weight at birth and head circumference were ing to the development of SG are shown in Table 2. The significantly higher in the SG-positive group (p < 0.001 average age in the SG group was remarkably lower than and p = 0.001; respectively). Additionally, significant in the other group (25.34 ± 3.44 years vs. 28.45 ± 4.61 years, differences were found between the two groups with respectively; p < 0.001). Prepregnancy BMI and postpreg- regard to infant sex. Male babies were significantly nancy BMI were significantly lower in the SG-negative higher in the SG-positive group than in the SG-negative group than in the SG-positive group. Additionally, abdom- group (p = 0.037). No noteworthy differences were noted inal circumference, hip circumference, and thigh circum- between 2 two groups with regard to gestational age ference were significantly higher in the SG-positive group. at birth and mode of delivery (p = 0.624 and p = 0.579, There was no statistically significant difference between respectively) (Table 3). groups about weight gain during pregnancy and daily Backward LR logistic regression analysis was per- water consumption. formed between parameters that were statistically sig- Significantly higher serum elastin concentrations nificant according to univariate analysis, such as the were found in pregnant women with SG compared to sex of the baby, acne condition, skin type, baby’s weight pregnant women without SG (99.46 ± 32.92 μg/mL vs. and head circumference, mother’s age, elastin level, and 88.36 ± 19.12 μg/mL, respectively; p = 0.018) (Table 2). anthropometric measurements, with a correlation of

Table 2: Comparison of variables between groups according to the presence or absence of striae gravidarum.

Group 1 (n = 33) Group 2 (n = 105) p-Value (mean ± SD) (mean ± SD)

Age (years) 28.45 ± 4.61 25.34 ± 3.44 <0.001 Height (m) 1.58 ± 0.03 1.60 ± 0.05 0.069 Prepregnancy weight (kg) 53.91 ± 5.83 67.91 ± 14.58 <0.001 Postpregnancy weight (kg) 66.36 ± 8.29 83.43 ± 14.51 <0.001 Weight gain (%) 23.66 ± 11.18 24.16 ± 9.96 0.805 Prepregnancy BMI (kg/m2) 21.59 ± 2.28 26.51 ± 4.93 <0.001 Postpregnancy BMI (kg/m2) 26.55 ± 2.97 32.62 ± 4.82 <0.001 Hip circumference (cm) 100.82 ± 6.82 114.60 ± 9.55 <0.001 Abdominal circumference (cm) 99.64 ± 6.78 113.66 ± 8.43 <0.001 Thigh circumference (cm) 57.00 ± 11.51 62.60 ± 6.78 0.001 Daily water consumption (L) 1.40 ± 0.57 1.58 ± 0.64 0.154 Elastin level (μg/mL) 88.36 ± 19.12 99.46 ± 32.92 0.018

Group 1, pregnant women without striae gravidarum; group 2, pregnant women with striae gravidarum. Values are provided as the mean ± standard deviation. p < 0.05 indicates statistical significance and marked with bold.

Table 3: Comparison of birth parameters between groups according to the presence or absence of striae gravidarum.

Group 1 (n = 33) Group 2 (n = 105) p-Value

Delivery method Vaginal birth 15 (26.3%) 42 (73.7%) 0.579 Cesarean 18 (22.2%) 63 (77.8%) Sex of the infant Boy 12 (16.7%) 60 (83.3%) 0.037 Girl 21 (31.8%) 45 (68.2%) Gestational age at delivery (weeks) 38.11 ± 1.68 38.21 ± 2.8 0.624 Birth weight of newborn (g) 3010.91 ± 425.6 3403.71 ± 453.9 <0.001 Head circumference of newborn (cm) 35.45 ± 0.79 35.88 ± 0.58 0.001

Table 4: Logistic regression analysis of significant factors (Backward LR).

Risk factor OR (95% CI)a p-Value

Sex of infant (boy compared with girl) 12.77 (1.64–99.47) 0.015 Acne (presence compared with absence) 25.43 (3.99–162.30) 0.001 Age (per 1 year increase) 0.60 (0.46–0.79) <0.001 Elastin (per 1 number increase) 1.05 (1.02–1.08) 0.002 Postpregnancy BMI (per 1 kg/m2 increase) 1.88 (1.42–2.50) <0.001

0.50 (Cox–Snell), 0.66 (Nagelkerke). Model χ2 (1) = 92.43, p = 0.001; aOR, Odds ratio; CI, confidence interval. p < 0.05 indicates statistical significance and marked with bold.

0.7 or greater. Other parameters included the mother’s [18]. Hereby, increased skin tension may lead to the degen- height, weight, BMI, weight gain, thigh circumference, eration of the skin at the striae zones. Increased glucocor- hip circumference, and abdominal circumference. ticoids during pregnancy suppress the production of the Our results showed that increased elastin level, acne collagen and elastin fibers, thus preventing renewal of the presence in mother, higher BMI after birth and male fibers, which adapts the skin to mechanical stress. infants increases the risk of SG. In the other hand, the However, despite a large number of studies, it is still risk of SG decreases as maternal age increases (Table 4). difficult to pinpoint the exact cause of striae formation and predict its occurrence. Once the striae is formed, the deformation of the skin is irreversible. The most effective Discussion method in the treatment of SG is to prevent its development by using prophylactic treatments. But according to Although SG does not cause serious health problems, it is the Cochrane Review, one of the largest studies ever made difficult to manage given aesthetic concerns, psychologi- about SG, topical agents have been reported to be unsuc- cal problems, and inability to predict the occurrence of SG, cessful in preventing the development of SG [19]. and the lack of definitive treatment SG is noted in 50–90% This research has shown that the reason behind of pregnancies [1–3]. In this study, the frequency of SG is the development of SG still remains unclear and further 76%. We noted that SG was linked with young maternal research is needed to clarify the etiopathogenesis to age; pre- and postpregnancy maternal weight and BMI; develop effective agents for prevention. The focus of our anthropometric measurements, such as hip, abdominal study was on the role of elastin turnover in the etiopatho- and thigh; acne presence during pregnancy and skin type, genesis of SG. which are coherent with previous study results [6, 7]. Elastin is an important scleroprotein located in con- In addition, male babies, high birth weight and head nective tissue, providing elasticity to skin upon expo- circumference of the newborn are associated with SG. In sure to mechanical stress. In our study, serum elastin contrast with previous studies [1, 2, 5], we did not deter- levels, which is an indicator of elastin turnover, were sig- mine any relationship between SG and smoking, family nificantly higher in SG-positive women than in women history, weight gain during pregnancy and daily water without SG. High serum elastin levels may be the result consumption. of a induced elastin production in women with SG. Wang As far as we know, mechanical skin tension and et al. investigated the anatomy of elastic fibers in striae increased estrogen, relaxin and adrenocortical hormone from healthy and lesional skin of pregnant women. The levels affect elastin fibers, collagen fibers and other extra- authors observed that a significant remodeling of the cuta- cellular matrix components and cause abnormalities that neous elastic fiber system occurred as a consequence of trigger the development of SG [13–15]. Hormones, such as the increased low-intensity load on the skin during preg- adrenocortical hormone and relaxin, reduce the adhesion nancy [11]. Due to these alterations, there was a marked between collagen fibers, which causes structural altera- disruption of the normal elastic fiber network. Elastin tions in elastin fibers and collagens and leads to reduced is produced by linking together many small soluble pre- solidity to tension [16, 17]. The studies showed that andro- cursor tropoelastin protein molecules. Interestingly, the gen, estrogen and glucocorticoid receptors were 2 times expression of the tropoelastin gene was dramatically ele- more frequent in striae tissues compared with normal skin. vated in SG [11], indicating that a considerable amount of This evidence indicates increased hormonal receptor activ- tropoelastin-rich fibrils were derived from de novo synthe- ity in skin areas that are exposed to mechanical tension sis by dermal fibroblasts. Amplification of the synthesis Beril Gürlek et al.: Elastin levels and striae gravidarum 81 of tropoelastin and fibrillin-1 may represent the skin’s Since striae development during pregnancy is influenced response to the disruption of normal elastic fibers, and by many variables such as genetic structure, skin type, this feature may promote increased serum elastin in SG as age, BMI, weight gain and gender, serum elastin level is show our study. not suitable for clinical purposes to predict the occur- Although the level of elastin is increased in tissue rence of SG. Considering all risk factors including elastin and serum, newly synthesized tropoelastin-rich fibers levels, SG may be predicted more accurately. In addition, cannot function as elastin fibers because they are thin many topical medical agents and laser treatment modali- and disorganized [20]. Therefore, high elastin levels in ties that prevent or heal the deformed skin are available serum cannot prevent the formation of striae; conversely, that are specially designed to stimulate collagen produc- it may represent the production of elastin caused by tion. However, very few of these treatment modalities mechanical tissue damage. Similar results were reported have focused on elastin production [20]. Better treatment by Watson et al., who observed a complex, nested elastic options that protect the skin structure under mechanical system in the normal skin [14]. However, they implied stress and increase the production of healthy elastin may that in skin affected by striae, the components of this be developed as the number of studies investigating the elastic fiber network were reduced and reorganized. In role of elastin in SG development increases. this setting, the elements of fibrillin and elastin were In conclusion, serum elastin levels are increased in affected equally. Mechanical pressure on the skin during women with SG. However, the newly synthesized elastin pregnancy can influence the elastic fiber network and may not be functional as it is thin and disorganized. There- trigger the remodeling that leads to the formation of fore, increased elastin production may not prevent the striae [14]. formation of striae. High serum elastin levels in SG may The most important limitations of our study are that be used for clinical purposes to predict the formation of we did not investigate elastin-derived peptides (EDP), striae and this finding may provide an impetus to explore which is known as another marker of elastin turnover. the pathomechanisms of striae. Further controlled trials Production and destruction rate of elastin fibrils increases on larger series are warranted to determine the predictive with the development of striae [11, 14], resulting soluble role and clinical significance of serum elastin levels in the elastin peptides to pass into bloodstream which may formation of SG. increase the serum EDP level. Although studies have used EDP as an indicator of elastin turnover in atherosclerosis Financial disclosure: There is no sponsorship or financial and aortic aneurysm [21], there is no study found investi- support in our work. gating the EDP level in SG in the literature. If we studied Ethical considerations: All procedures performed were in the level of serum EDP in our study, we could show both accordance with the ethical standards of the institutional the production and destruction of elastin in a bidirection- and/or national research committee and with the 1964 ally. However, our hypothesis was that the most important Helsinki Declaration and its later amendments or compa- factor in the stria etiopathogenesis in pregnant women rable ethical standards. Informed consent was obtained was the problems caused by the production of elastin from all individual participants included in the study. rather than destruction. Therefore, we evaluated only the Conflict of interests: The authors declare that they have serum elastin level, assuming that it would reflect the no conflict of interests. production of elastin better. Since our study is the first study in which serum samples are used to analyze SG, we believe that our study will inspire researchers to investigate other markers of elastin turnover. References The other limitations of the present study include data 1. Salter SA, Kimball AB. Striae gravidarum. Clin Dermatol restricted to the experience of a single center and possible 2006;24:97–100. impacts of genetic, metabolic and environmental factors 2. Chang AL, Agredano YZ, Kimball AB. Risk factors associated with on serum elastin levels. striae gravidarum. J Am Acad Dermatol 2004;51:881–5. To our best knowledge, there is no study designed to 3. Yamaguchi K, Suganuma N, Ohashi K. Quality of life evaluation evaluate serum elastin levels in pregnant women with SG. in Japanese pregnant women with striae gravidarum: a cross- Our results revealed high serum elastin levels in women sectional study. BMC Res Notes 2012;5:450. 4. Lawley TJ, Yancey KB. Skin changes and diseases in pregnancy. with SG as a marker of increased elastin turnover. These In: Freedberg IM, Eisen AZ, Wolf K, Austen KF, Goldsmith LA, Katz findings are in conjunction with previous studies that SI, et al., editors. Fitzpatrick’s dermatology in general medicine, indicate the critical role of elastin in the striae formation. 5th ed. New York: McGraw Hill, 1999:1963–9. 82 Beril Gürlek et al.: Elastin levels and striae gravidarum

5. Atwal GS, Manku LK, Griffiths CE, Polson DW. Striae gravidarum 13. Lurie S, Matas Z, Fux A, Golan A, Sadan O. Association of serum in primiparae. Br J Dermatol 2006;155:965–9. relaxin with striae gravidarum in pregnant women. Arch Gynecol 6. Thomas RG, Liston WA. Clinical association of striae gravidarum. Obstet 2011;283:219–22. J Obstet Gynecol 2004;24:270–1. 14. Watson RE, Parry EJ, Humphries JD, Jones CJ, Polson DW, Kielty 7. Buchanan K, Fletcher HM, Reid M. Prevention of striae CM, et al. Fibrillin microfibrils are reduced in skin exhibiting gravidarum with cocoa butter cream. Int J Gynaecol Obstet striae distensae. Br J Dermatol 1998;138:931–7. 2010;108:65–68. 15. Watson RE. Remodelling of elastic fibres in striae gravidarum. 8. Petersen E, Wagberg F, Anquist KA. Serum concentrations of Br J Dermatol 2015;173:1359–60. elastin-derived peptides in patients with specific manifesta- 16. Tunzi M, Gray GR. Common skin conditions during pregnancy. tions of atherosclerotic disease. Eur J Vasc Endovasc Surg Am Fam Physician 2007;75:211–8. 2002;24:440–4. 17. Osman H, Rubeiz N, Tamim H, Nassar AH. Risk factors for 9. Tzvetanov P, Hegde V, Al-Hashel JY, Atanasova M, Sohal AP, the development of striae gravidarum. Am J Obstet Gynecol Roussef RT. Abnormal levels of serum anti-elastin antibodies in 2007;196:62.e1–5. patients with symptomatic carotid stenosis. Clin Neurol Neuro- 18. Cordeiro RC, Zecchin KG, de Moraes AM. Expression of estrogen, surg 2014;116:9–12. androgen, and glucocorticoid receptors in recent striae disten- 10. Lewis KG, Bercovitch L, Dill SW, Robinson-Bostom L. Acquired sae. Int J Dermatol 2010;49:30–2. disorders of elastic tissue: Part I. Increased elastic tissue and 19. Brennan M, Young G, Devane D. Topical preparations for pre- solar elastotic syndromes. J Am Acad Dermatol 2004;51:1–21. venting stretch marks in pregnancy. In: Cochrane Database Syst 11. Wang F, Calderone K, Do TT, Smith NR, Helfrich YR, Johnson Rev 2012;11:CD000066. TR, et al. Severe disruption and disorganization of dermal 20. Elsaie ML, Baumann LS, Elsaaiee LT. Striae distensae (stretch collagen fibrils in early striae gravidarum. Br J Dermatol marks) and different modalities of therapy: an update. Dermatol 2018;178:749–60. Surg 2009;35:563–73. 12. Fitzpatrick TB. The validity and practically of sun-reactive skin 21. Qin Z. Soluble elastin peptides in cardiovascular homeostasis: types I through VI. Arch Dermatol 1988;124:869–71. foe or ally. Peptides 2015;67:64–73.