ABSTRACT
BACKGROUND: Hypertension (HTN) is one of the leading causes of morbidity and mortality worldwide. A prompt diagnosis and treatment of hypertensive retinopathy (HR), the leading complication of HTN is pivotal for a better visual outcome. Increased blood pressure on its own cannot fully clarify the development of retinal alterations, therefore an additional pathogenetic mechanism, such as oxidative stress, might be inquired.The aim of the study was to evaluate the changes in the level of ischemia modified albumin (IMA) in the serum and tears of HR patients in order to establish the predictive value of IMA for the HR progression. METHODS: Serum and tear samples for the measurement of IMA were collected from 90 patients detected primarily with HR, who were not taking any antihypertensive or other drug that could influence the results of the study, divided according to the Keith-Wagener classification into GI - 36 patients with HR grade I, GII - 35 with HR grade II and GIII - 19 with HR grade III. Serum and tear IMA levels were assessed using the Co2+ binding method and expressed as median and interquartile range. Kruskal-Wallis and Mann-Whitney nonparametric tests were used to compare the groups and the Spearman correlation coefficient was calculated (SPSS 23.0), with p<0.05 being statistically significant. RESULTS: The groups showed a statistically significant difference in serum IMA (p=0.006), the values increasing in parallel with the progression of HR. The serum IMA level in GII increased compared to GI (+3%; 239.06 µM/L (IQR 75.58) vs 231.77 µM/L (IQR 104.09), p=1.00), as well as in GIII patients compared to GII (+17%; 277.67 µM/L (IQR 88.72) vs 239.06 µM/L (IQR 75.58), p=0.04). There were no differences in IMA content (p=0.160), between groups in the tears. No correlations were found between serum and tear IMA levels (p=0.134), but serum IMA showed a significant moderate strength, positive correlation with the degree of HR (r=0.307, p=0.003). CONCLUSION: A progressive enhancement in serum IMA level as HR advanced was identified. Thereby, the results suggest the potential relevance of serum IMA as a sensitive and early biomarker useful for grading and optimal treatment of the patients with HR.
ABSTRACT
PURPOSE: To evaluate the activity of Renin-Angiotensin (SRA) and Kinin-Kalikrein (SKK) systems in patients with primary open-angle glaucoma (POAG) in tears, blood and aqueous flow. METHODS: Components of SRA and SKK were analysed in the blood, tears and aqueous flow of 38 patients found in different stages of POAG. The samples of aqueous flow were harvested during glaucoma surgery The results were compared to those from a healthy group of patients (for tears and blood) and to a group of normal patiens that had ocular surgery for cataract and high ametropias (for samples af aqueous flow). RESULTS: In patients with high pressure primary open-angle glaucoma, when comparing them to those from the control group, the measurements showed: a high level of angiotensin converting enzyme (ACE) activity (in tears up to 108-125%, p < 0.001 and in aqueous flow up to 40-47% p < 0.001), a high level of kalikrein (in tears up to 21-29%, p < 0.001 and in aqueous flow up to 35-44% p < 0.001) and a high level of the summed activity of prekalikrein +kalikrein (up to 11-14, p < 0.001). A decrease in the prekalikrein/kalikrein ratio was found (up to 21-25% p < 0.01 in tears and aqueous flow) and this decrease was proved to be in direct correlation to the glaucoma stages of evolution. A decrease in prekalikrein activity was also found; up to 7% in the tears for each developing glaucoma stage. After the glaucoma surgery, the levels of ACE activity and kalikrein measured in tears decreased (up to 17% p < 0.001 and 17% p < 0.001 respectively) without reaching the levels in the normal group while the levels of prekalikrein and the prekalikrein/kalikrein ratio grew (up to 7% p < 0.01 and 16% < 0.001 respectively). CONCLUSIONS: The results show a high level of kalikrein and angiotensin converting enzyme (ACE) activity (measured in aqueous flow and tears) when comparing the group with POAG to the normal group. A decrease in prekalikrein activity was found, and the prekalikrein/kalikrein ratio was also low in the aqueous flow and tears. After the glaucoma surgery the levels of ACE activity and kalikrein decreased without reaching the levels in the normal group while the levels of prekalikrein and the prekalikrei/kalikrein ratio grew.
