Relationship between oxygen tension, oxidative stress and vascular ageing among the general population of Vijayapur urban area: A cross sectional approach

Abstract

Objective: We aimed to assess the influence of oxygen tension or oxygen microenvironment in vivo including oxidative stress on age and gender associated changes in vascular health among general population of Vijayapur urban area. Methods: The present cross-sectional study conducted in Sri B.M. Patil Medical College (October 2016 to April 2017) on 204 healthy subjects male (n= 102) and female (n=102) subjects (20-95 years) were randomly selected among general population of Vijayapur city, Karnataka, India. Subjects were divided into six group: Group I (20-29 years), II (30-39 years), III (40-49 years), IV (50-59 years), V (60-69 years) and VI (>70 years). The following parameters were tested: Anthropometric parameters: height (cms), weight (kg), BMI (kg/m2) and BSA (m2); Physiological parameters: pulse rate in (beats/min), systolic blood pressure (mmHg), diastolic blood pressure (mmHg), pulse pressure (mmHg) and mean arterial pressure (mmHg); Hematological parameters: RBC, WBC, HB%, PCV, Platelet count and blood indices like MCV, MCH, MCHC; biochemical parameters: fasting blood glucose (FBS), serum triglyceride, serum cholesterol, serum HDL, serum LDL, serum VLDL; Arterial stiffness parameters: Brachial-ankle pulse wave velocity (baPWV), carotid femoral pulse wave velocity (c-f PWV), augmentation index (AIx@75), arterial stiffness index at brachial (bASI) and tibial arteries (aASI); Oxidative and nitrosative stress measure: serum malondialdehyde (MDA), serum nitric oxide (sNOx) concentration; and Antioxidant capacity: serum superoxide dismutase (SOD) activity, erythrocyte reduced glutathione (GSH), serum ascorbic acid or vitamin C; Oxygen sensing molecular markers: serum erythropoietin (Epo) and vascular endothelial growth factor (VEGF). Statistical analysis was done by using one-way ANOVA followed by post-hoc t-test and unpaired t-test by using SPSS softwar Results: Group I to group VI showed significant (p<0.001) steady increase of PWV, ASI, AIx and MAP in both male and females with concomitant significant decrease of serum NOx in both male and female subjects. Further a significant (p=0.000) negative correlation between b-aPWV and c-f PWV with NOx in both male and female subjects were also observed. Observed significant (p<0.001) increased MDA and decreased SOD, GSH and Vit C levels in both males and females in association with age. Also observed significant (p<0.001) increased serum VEGF and decreased Epo level with ageing among both male and female participants. Conclusion: PWV may be considered as more reliable marker than MAP to evaluate age associated arterial stiffness. Epo might be playing a crucial homeostatic role in ageing. Females have an augmented protection against age related alteration of vascular pathophysiology due to greater VEGF concentration as compared to their male counterparts. Endothelial function is not the final protection for arterial function as role of VEGF and its expression in arterial smooth muscles is very important for vascular stability. Understanding of these mechanisms may support greater pharmaco physiological understanding of arterial stiffness which may possibly improve cardiovascular health of an individual irrespective to their sex.