Evaluation of renin and angiotensin II levels in pseudoexfoliation syndrome / Avaliação dos níveis de renina e angiotensina II na síndrome de pseudo-exfoliação

ABSTRACT Purpose: Pseudoexfoliation syndrome has been linked to impaired function of the heart and blood vessels. We conducted a study to investigate the role of the renin-angiotensin system in the etiopathogenesis of pseudoexfoliation syndrome. Methods: The subjects were 14 patients with pseudoexfoliation syndrome and 14 healthy controls who underwent cataract extraction. Preoperative 5-ml samples of peripheral venous blood and perioperative aqueous humor were collected from the patients in both groups. Plasma and aqueous humor renin levels were analyzed by an immunoradiometric method, and angiotensin II levels were analyzed by radioimmunassay. SPSS version 16.0 was used for statistical analyses. A p-value <0.05 was considered to indicate a statistically significant difference. Results: The mean ages of the patients in pseudoexfoliation and control groups were 71.7 ± 7.1 and 67.4 ± 9.3 years, respectively (p=0.140). The median aqueous humor renin level was 7.73 pg/ml (4.15-21) in the control group and 11.95 pg/ml (3.75-18.54) in pseudoexfoliation group (p=0.022). There were no differences between the two groups in the plasma renin, plasma angiotensin II, or aqueous humor angiotensin II levels. The correlations between plasma and aqueous humor renin levels and between plasma and aqueous humor angiotensin II levels were examined separately for each group; no significant correlations were observed in pseudoexfoliation group (r=-0.440, p=0.115; r=-0.414, p=0.142) or the control group (r=-0.232, p=0.425; r=0.482, p=0.081). Conclusion: Aqueous humor renin levels are higher in pseudoexfoliation syndrome. The results indicate a probable role of renin-angiotensin system in pseudoexfoliation syndrome. Further studies with larger numbers of cases are needed to clarify the precise association of renin-angiotensin system with the etiopathogenesis of pseudoexfoliation syndrome.

RESUMO Objetivo: A síndrome de pseudo-exfoliação tem sido associada ao comprometimento da função do coração e dos vasos sanguíneos. Foi realizado um estudo para investigar o papel do sistema renina-angiotensina na etiopatogenia da síndrome de pseudo-exfoliação. Métodos: Os sujeitos foram 14 pacientes com síndrome de pseudo-exfoliação e 14 controles saudáveis submetidos à extração de catarata. Amostras pré-operatórias de 5 ml de sangue venoso periférico e humor aquoso perioperatório foram coletadas dos pacientes em ambos os grupos. Os níveis de renina no plasma e humor aquoso foram analisados pelo método imunorradiométrico e os níveis de angiotensina II foram analisados por radioimunoensaio. O SPSS versão 16.0 foi utilizado para análises estatísticas. Considerou-se o valor de p<0,05 para indicar uma diferença estatisticamente significativa. Resultados: A média de idade dos pacientes nos grupos pseudo-exfoliação e controle foi de 71,7 ± 7,1 e 67,4 ± 9,3 anos, respectivamente (p=0,140). O nível médio de renina no humor aquoso foi de 7,73 pg / ml (4,15-21) no grupo controle e 11,95 pg/ml (3,75-18,54) no grupo pseudo-exfoliação (p=0,022). Não houve diferenças entre os dois grupos de renina plasmática, angiotensina II plasmática ou nos níveis de angiotensina II em humor aquoso. As correlações entre os níveis de renina no plasma e no humor aquoso e entre os níveis de angiotensina II no plasma e humor foram examinadas separadamente para cada grupo; n]ao foram observadas correlações significativas no grupo pseudo-exfoliação (r=-0,440, p=0,115; r=-0,414, p=0,142) ou no grupo controle (r=-0,232, p=0,425; r=0,482, p=0,081). Conclusão: Os níveis de renina no humor aquoso são mais elevados na síndrome de pseudo-exfoliação. Os resultados indicam um provável papel do sistema renina-angiotensina na síndrome de pseudo-exfoliação. Novos estudos com maior número de casos são necessários para esclarecer a associação precisa do sistema renina-angiotensina com a etiopatogenia da síndrome de pseudo-exfoliação.

Evaluation of renin and angiotensin II levels in pseudoexfoliation syndrome.

PURPOSE: Pseudoexfoliation syndrome has been linked to impaired function of the heart and blood vessels. We conducted a study to investigate the role of the renin-angiotensin system in the etiopathogenesis of pseudoexfoliation syndrome. METHODS: The subjects were 14 patients with pseudoexfoliation syndrome and 14 healthy controls who underwent cataract extraction. Preoperative 5-ml samples of peripheral venous blood and perioperative aqueous humor were collected from the patients in both groups. Plasma and aqueous humor renin levels were analyzed by an immunoradiometric method, and angiotensin II levels were analyzed by radioimmunassay. SPSS version 16.0 was used for statistical analyses. A p-value <0.05 was considered to indicate a statistically significant difference. RESULTS: The mean ages of the patients in pseudoexfoliation and control groups were 71.7 ± 7.1 and 67.4 ± 9.3 years, respectively (p=0.140). The median aqueous humor renin level was 7.73 pg/ml (4.15-21) in the control group and 11.95 pg/ml (3.75-18.54) in pseudoexfoliation group (p=0.022). There were no differences between the two groups in the plasma renin, plasma angiotensin II, or aqueous humor angiotensin II levels. The correlations between plasma and aqueous humor renin levels and between plasma and aqueous humor angiotensin II levels were examined separately for each group; no significant correlations were observed in pseudoexfoliation group (r=-0.440, p=0.115; r=-0.414, p=0.142) or the control group (r=-0.232, p=0.425; r=0.482, p=0.081). CONCLUSION: Aqueous humor renin levels are higher in pseudoexfoliation syndrome. The results indicate a probable role of renin-angiotensin system in pseudoexfoliation syndrome. Further studies with larger numbers of cases are needed to clarify the precise association of renin-angiotensin system with the etiopathogenesis of pseudoexfoliation syndrome.