Serum Dehydroepiandrosterone Sulphate Level in Age-related Macular Degeneration

Serum Dehydroepiandrosterone Sulphate Level in Age-related Macular Degeneration CENGAVER TAMER, MD, HÜSEYIN OKSUZ, MD, AND SADIK SÖG˘ÜT, MD

● PURPOSE:

To evaluate plasma dehydroepiandrosterone sulphate (DHEAS) levels in patients diagnosed with age-related macular degeneration (AMD) and controls. ● DESIGN: Case-controlled, prospective, comparative noninterventional study. ● METHODS: This study involved 32 men and 35 women with exudative AMD, 37 men and 38 women with nonexudative AMD, and 32 men and 32 women of an age-matched control group. The Wisconsin Age-Related Maculopathy Grading System was used to asses the severity of AMD lesions. DHEAS levels were measured and compared according to a gender based subdivision. Analysis of variance was used to assess the association between DHEAS and AMD. Linear regression model was used to examine the relation among DHEAS level and AMD severity scale. ● RESULTS: Mean ⴞ SD of DHEAS levels in exudative AMD, nonexudative AMD, and controls in men was 2.67 ⴞ 0.68 ␮mol/l, 2.89 ⴞ 0.95 ␮mol/l, and 4.43 ⴞ 1.44 ␮mol/l, respectively (P ⴝ .001), and in women was 1.64 ⴞ 0.72 ␮mol/l, 1.85 ⴞ 0.73 ␮mol/l, and 2.78 ⴞ 0.91 ␮mol/l, respectively (P ⴝ .001). Post hoc Tukey analyses revealed a significant reduction in serum DHEAS level in both AMD groups, compared with controls for men and women (P ⴝ .001), while no difference was found between AMD groups in both men and women (P ⴝ .668 and 0.49, respectively). Regression analyses revealed an inverse correlation among serum DHEAS level and AMD severity scale both in men and women (P ⴝ .006 and .007, respectively). ● CONCLUSIONS: This study suggests an inverse correlation between serum DHEAS level and AMD severity scale with a considerably reduced DHEAS level in AMD. (Am J Ophthalmol 2007;143:212–216. © 2007 by Elsevier Inc. All rights reserved.)

Accepted for publication Sept 20, 2006. From the Ophthalmology Department (C.T., H.O.) and the Biochemistry Department (S.S.), Mustafa Kemal University, Antakya, Turkey. Inquiries to Cengaver Tamer, MD, Mustafa Kemal University, Ophthalmology Department, 03110 Antakya (Antiochia), Hatay/Turkey; e-mail: [email protected]

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GE RELATED MACULAR DEGENERATION (AMD) IS

the leading cause of visual loss in the elderly.1,2 AMD has two main presentations, nonexudative and exudative. Age, heredity, hypertension, atherosclerosis, hypercholesterolemia, and smoking are well-known risk factors.3 Previous studies have shown that oxidative stress from reactive oxygen species is one of the key factors in the pathogenesis of AMD.4 –7 In an in vitro study, Bucolo and associates have shown that oxidative injury to retinal pigment epithelial cells can be attenuated by dehydroepiandrosterone sulphate (DHEAS) treatment.8 Previous studies have shown similar protective effects of DHEAS against oxidative insult on other neuronal cells.9 Recent studies suggest that DHEAS may exert a significant influence on the structural organization, functional activity, and/or pathological features of many ocular tissues including retinal pigment epithelium (RPE).10,11 Sex steroids have also shown to have beneficial effects on atherosclerosis and hypertension,12,13 which are risk factors for AMD development and progression. Dehydroepiandrosterone and its sulphate conjugate are the major secretory steroidal products of the human adrenal glands.14 The secretion of DHEAS is stimulated by adenocorticotrophic hormone (ACTH), its serum level peaks by the second decade, and then, declines steadily by an average of about 10% per decade15,16 and, an inverse correlation of serum DHEAS level with numerous age-related sequelae have been documented previously.17 The major aim of the current study is to determine whether there is an association between AMD and serum DHEAS levels.

METHODS ● STUDY

SUBJECTS: This case-controlled, prospective, comparative noninterventional study was conducted in the outpatient ophthalmology clinics of a university-affiliated medical institution. The study protocol was approved by the Human Studies committee of the Mustafa Kemal University (MKU) and was conducted in accordance with guidelines established by the Declaration of Helsinki. Written informed consent was obtained from every participant. The study consisted of 67 patients (32 men, 35 women with a mean age of 66.6 ⫾ 7.0 and 65.5 ⫾ 5.3, respectively) with exudative

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TABLE. Characteristics of the Study Samples Characteristics

Exudative AMD

Nonexudative AMD

P value ⫽ ANOVA

Control

Gender

么(n ⫽ 32)

乆(n ⫽ 35)

么(n ⫽ 37)

乆(n ⫽ 38)

么(n ⫽ 32)

乆(n ⫽ 32)

么

乆

Age Weight (kg) BMI (kg/m2)

66.6 ⫾ 7.0 79.2 ⫾ 0.8 25.5 ⫾ 0.2

65.5 ⫾ 5.3 66.7 ⫾ 08 25.5 ⫾ 0.3

67.4 ⫾ 4.5 77.9 ⫾ 0.8 24.5 ⫾ 0.2

66.4 ⫾ 4.0 67.8 ⫾ 0.9 25.8 ⫾ 0.3

66.3 ⫾ 4.3 76.3 ⫾ 0.7 24.6 ⫾ 0.2

65.7 ⫾ 3.9 67.0 ⫾ 0.8 25.7 ⫾ 0.3

.684 .532 .538

.663 .541 .631

AMD ⫽ age-related macular degeneration; ANOVA ⫽ analysis of variance; BMI ⫽ body mass index; 么⫽ male; 乆 ⫽ female. Data represent ⫽ mean ⫾ SD.

AMD, 75 patients with nonexudative AMD (37 men, 38 women with a mean age of 67.4 ⫾ 4.5 and 66.4 ⫾ 4.0, respectively), and a control group of 66 age-matched subjects (32 men, 32 women, with a mean age of 66.3 ⫾ 4.9 and 65.7 ⫾ 3.9, respectively). Subjects were recruited into the study over a 22-month period. All participants underwent a complete ophthalmic examination consisting of best-corrected visual acuity, slit-lamp biomicroscopy, dilated funduscopy, and color fundus photography with fundus fluorescein angiography when necessary. A complete medical history was also obtained, including hormonal abnormalities, renal disease, hypertension, smoking, and medications that may alter hormonal status such as glucocorticoids, statins, ␤-blockers, psychotrophics, hormonal replacement therapy, or hormonal inhibitors. The Wisconsin Age-Related Maculopathy Grading System was used to assess the presence and severity of lesions associated with AMD. For each eye, a six-level severity scale for AMD was defined as follows:18 Level 10: No drusen of any type, or hard drusen, or small soft drusen (⬍125 ␮m in diameter) only, regardless of area of involvement, and no pigmentary abnormality (increased retinal pigment or RPE depigmentation) present. Level 20: Hard drusen or small soft drusen (⬍125 ␮m in diameter), regardless of area of involvement, with pigmentary abnormalities present, or soft drusen (ⱖ125 ␮m in diameter) with drusen area ⬍196,350 ␮m2 (equivalent to a circle with a diameter of 500 ␮m) and no pigmentary abnormalities present. Level 30: Soft drusen (ⱖ125 ␮m in diameter) with drusen area ⬍196,350 ␮m2 and pigmentary abnormalities present or soft drusen (ⱖ125 ␮m in diameter) with drusen area ⱖ196,350 ␮m2 with or without increased retinal pigment but no RPE depigmentation present. Level 40: Soft drusen (ⱖ125 ␮m in diameter) with drusen area ⱖ196,350 ␮m2 involvement and RPE depigmentation present with or without increased retinal pigment. Level 50: Pure geographic atrophy in absence of exudative macular degeneration. Level 60: Exudative macular degeneration with or without geographic atrophy present. Exudative AMD comprised RPE detachment, serous detachment of the sensory retina, subretinal haemorrhage, subretinal fibrous scars, or all of these. The nonexudative AMD group consisted of patients with AMD findings more than or equal to level 20. VOL. 143, NO. 2

Controls were consecutive patients undergoing cataract surgery in the same clinic during the same time period. A pool of 117 blood samples was available, from which the patients in the control group were matched with the AMD groups for age and gender. Body mass index (BMI) of every subject enrolled in the study was also calculated as it may affect the hormone levels. Subjects were chosen among nonsmokers excluding any subject with a chronic illness or subjects taking glucocorticoids, ␤-blockers, or psychotropic medications, all of which can alter reproductive hormone dynamics, were not enrolled in the study.19 Blood samples were drawn for the detection of serum DHEAS levels by venapuncture from fasting subjects at the ophthalmology ward between 8:30 AM and 9:00 AM. Intraassay coefficients of variation, determined on the basis of duplicate results of internal quality control pools with three different levels of analyte. DHEAS level was measured in serum by an automated immunoenzymatic assay, on the Serono SR1 analyzer (Serono, Milan, Italy). The correlation coefficient with standard radio immune assay (RIA) was r ⫽ .98.20 The lower detection limit of the assay was 0.044 ␮mol/l. The intraassay coefficient of variation was 6%. ● STATISTICAL ANALYSES: DHEAS levels in both gender subgroups of exudative AMD, nonexudative AMD, and control groups were measured. The results were analyzed separately for men and women. Statistical analyses were achieved with one-way analysis of variance (ANOVA) followed by post hoc multiple comparisons with the Tukey honestly significant difference (HSD) test. General linear regression models were used to evaluate the associations between plasma DHEAS level and severity of AMD. A P value less than .05 was considered statistically significant. Statistical analyses were performed using software SPSS version 11.5 (SPSS Inc, Chicago, Illinois, USA).

RESULTS DEMOGRAPHIC AND CLINICAL DATA OF THE NONEXUDA-

tive and exudative types of AMD patients and controls are documented in the Table. There were no statistically significant differences among the groups according to

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FIGURE 3. Scatter graph showing an inverse correlation between serum dehydroepiandrosterone sulphate (DHEAS) level and age-related macular degeneration (AMD) severity scale in men ( r ⴝ .330, P ⴝ .006; Linear regression model). Each circle stands for one patient.

FIGURE 1. Box-plot showing the distribution of serum dehydroepiandrosterone sulphate (DHEAS) level in exudative agerelated macular degeneration (AMD), nonexudative AMD, and control groups in men (P ⴝ .001; analysis of variance [ANOVA]).

FIGURE 4. Scatter graph showing an inverse correlation between serum dehydroepiandrosterone sulphate (DHEAS) level and age-related macular degeneration (AMD) severity scale in men (r ⴝ .315, P ⴝ .007; Linear regression model). Each circle stands for one patient.

FIGURE 2. Box-plot showing the distribution of serum dehydroepiandrosterone sulphate (DHEAS) level in exudative agerelated macular degeneration (AMD), nonexudative AMD, and control groups in women (P ⴝ .001; analysis of variance [ANOVA]).

men was 2.67 ⫾ 0.68 ␮mol/l, 2.89 ⫾ 0.95 ␮mol/l, and 4.43 ⫾ 1.44 ␮mol/l, respectively and, in women was 1.64 ⫾ 0.72 ␮mol/l, 1.85 ⫾ 0.73 ␮mol/, and 2.78 ⫾ 0.91 ␮mol/l, respectively. Evaluation of DHEAS levels of the three diagnostic groups in men and women revealed a significant

gender subgroups with regard to age, weight, and body mass index (P ⬎ .05; ANOVA). Mean ⫾ SD of DHEAS levels in exudative AMD, nonexudative AMD, and controls in 214

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difference (P ⫽ .001 and .001, respectively; ANOVA). There was no significant difference in DHEAS levels of the exudative and nonexudative AMD groups both in men and women according to post hoc (Tukey) analyses (P ⫽ .668 and .49, respectively). The DHEAS levels of control group were found to be significantly higher compared with exudative and nonexudative AMD groups in both men and women (P ⫽ .001; post hoc Tukey analyses). Figures 1 and 2 show the distribution of DHEAS levels of the three diagnostic groups in men and women. On linear regression analysis, an inverse correlation among serum DHEAS level and AMD severity scale was found both in men and women AMD patients (r ⫽ .330, P ⫽ .006 and r ⫽ .315, P ⫽ .007, respectively). Scatter graphs of regression analyses of men and women patients with AMD are presented in Figures 3 and 4.

DISCUSSION IN THE CURRENT STUDY, WE HAVE FOUND A SIGNIFICANT

decrease of DHEAS level in both nonexudative and exudative AMD patients of both gender subgroups compared with age matched controls. The serum DHEAS levels were found to be inversely correlated with the scale of AMD severity in both men and women. The exact cause of AMD is unknown. The risk factors for AMD include age, heredity, hypertension, atherosclerosis, smoking, and hypercholesteremia. Oxidative damage is the key factor for the onset and progression of the disease.4 –7,21 This theory is supported by numerous epidemiologic studies.22,23 Vision loss in AMD occurs through photoreceptor damage in the macula, with abnormalities in the RPE and the Bruch membrane.24 Studies have demonstrated that apoptotic cells are present in the RPE of eyes with AMD, indicating that apoptosis in RPE cells could contribute to AMD.25,26 Because of its anatomic location, the RPE is primed for oxidant and free radical production and has an extraordinary need for antioxidant protection.5,27,28 Retinal pigment epithelial cells generate H2O2 during phagocytosis and degradation of rod and cone outer segments, leading to DNA damage.29 Bucolo and associates showed in an in vitro study that H2O2-mediated damage on RPE cells can be attenuated by DHEAS treatment in a dose related manner.8 Bucolo and Drago have also shown that DHEAS and 17-␤-estradiol (which is also driven from DHEA-S in peripheral tissues) may prevent degeneration of RPE attributable to ischemia-reperfusion injury in a rat model by affecting the metabolic state of neurons and glial cells at least in part, through involvement of sigma 1 recognition sites.30 In another experimental study done on rabbits, Bednarek and associates have shown that DHEA administration can improve superoxide dismutase activity in platelets, which protects the RPE against oxidative damage.31 Potent androgens that are derived from DHEAS have been shown to have receptor proteins in the human VOL. 143, NO. 2

ocular tissues including RPE cells by Rocha and associates. They also found mRNAs for types 1 and 2, and 5 ␣-reductase in the human RPE cells.10 However, the exact mechanisms by which DHEAS protect human RPE cells against oxidative insult are not clear. In contrast to our findings, recent data from a population based study done by Defay and associates (the POLA Study Group) on women showed a positive relation between early stages of AMD and DHEAS levels32. However, it was not designed as a case controlled study and the probable effects of drugs like glucocorticoids, ␤-blockers, or psychotropic medications, which are not uncommonly used in AMD patients, were not eliminated and, as the authors stated, the statistical power of their study was very low for late AMD. At present, there are few successful medical interventions that can prevent AMD.33 The impact of the disease on the quality of life of the expanding elderly population is rising. For these reasons, further research needs to be directed at the primary and secondary prevention of AMD. Thus, the identification of modifiable factors related to this disease is an extremely important public health issue because it will facilitate and maximize the potential of appropriate interventions aimed at decreasing the prevalence and incidence of visual loss attributable to AMD. According to the results of the current study, DHEAS may be encountered as such a factor related to AMD, however, further prospective studies are needed to examine the possible role of DHEAS in AMD, and whether supplemental treatment with DHEAS may modify its natural history.

THE AUTHORS INDICATE NO FINANCIAL SUPPORT OR FInancial conflict of interest. Involved in the design of study (C.T.); Involved in conduct of study (C.T., H.O., S.S.); Involved in interpretation of the data (C.T., S.S.); and involved in the preparation of the manuscript (C.T.).

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20. Berr C, Lafont S, Debuire B, Dartigues JF, Baulieu EE. Relationships of dehydroepiandrosterone sulfate in the elderly with functional, psychological, and mental status, and short-term mortality: a French community based study. Proc Natl Acad Sci USA 1996;93:13410 –13415. 21. Beatty S, Koh H, Phil M, Henson D, Boulton M. The role of oxidative stress in the pathogenesis of age-related macular degeneration. Surv Ophthalmol 2000;45:115–134. 22. The Eye Disease Case-Control Study Group. Risk factors for neovascular age-related macular degeneration: the Eye Disease Case-Control Study Group. Arch Ophthalmol 1992; 110:1701–1708. 23. Aged-Related Eye Disease Study Research Group. A randomized, placebo-controlled, clinical trial of high-dose supplementation with vitamins C and E and beta carotene for age-related cataract and vision loss: AREDS Report No. 9. Arch Ophthalmol 2001;119:1439 –1452. 24. Young RW. Pathophysiology of age-related macular degeneration. Surv Ophthalmol 1987;31:291–306. 25. Ishibashi T, Sorgente N, Patterson R, Ryan SJ. Pathogenesis of drusen in the primate. Invest Ophthalmol Vis Sci 1986; 27:184 –193. 26. Dunaief JL, Dentchev T, Ying GS, Milam AH. The role of apoptosis in age-related macular degeneration. Arch Ophthalmol 2002;120:1435–1442. 27. Alder VA, Cringle SJ. The effect of the retinal circulation on vitreal oxygen tension. Curr Eye Res 1985;4:121–129. 28. Rozanowska M, Jarvis-Evans J, Korytowski W, Boulton ME, Burke JM, Sarna T. Blue light-induced reactivity of retinal age pigment: in vitro generation of oxygen-reactive species. J Biol Chem 1995;270:18825–18830. 29. Miceli MV, Liles MR, Newsome DA. Evaluation of oxidative processes in human pigment epithelial cells associated with retinal outer segment phagocytosis. Exp Cell Res 1994;214: 242–249. 30. Bucolo C, Drago F. Effects of neurosteroids on ischemiareperfusion injury in the rat retina: role of sigma 1 recognition sites. Eur J Pharmacol 2004;498:111–114. 31. Bednarek-Tupikowska G, Gosk I, Szuba A, et al. Influence of dehydroepiandrosterone on platelet aggregation, superoxide dismutase activity and serum lipid peroxide concentrations in rabbits with induced hypercholesterolemia. Med Sci Monit 2000;6:40 – 45. 32. Defay R, Pinchinat S, Lumbroso S, et al. Sex steroids and age-related macular degeneration in older French women: the POLA Study. Ann Epidemiol 2004;14:202–208. 33. Aged-Related Eye Disease Study Research Group. A randomized, placebo-controlled clinical trial of high dose supplementation with vitamins C and E, beta carotene and zinc for age-related macular degeneration and vision loss: AREDS Report No. 8. Arch Ophthalmol 2001;119:1417–1436.

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Biosketch Cengaver Tamer, MD, is an Assistant Professor of Ophthalmology at Mustafa Kemal University, Antiochia, Turkey, since 2004. He received his medical degree from Hacettepe University, Ankara, Turkey, in 1991. He completed his residency in Ophthalmology at Ankara University Eye Bank, Turkey, in 1997. Dr Tamer worked as an instructor in Ankara Numune training and research hospital vitreoretinal department from 1997 to 2004. Dr Tamer’s areas of research interests are vitreoretinal diseases and effects of sex steroids on the eye.

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