Free Radicals, Oxidative Stress-Related Diseases and Antioxidant Supplementation.

Though free radicals have beneficial roles in the body to fight against certain pathogenic diseases as well as are implicated in a number of cellular and physiological activities, elevated levels may be overwhelming for the antioxidant defense system to maintain the normal homeostatic state. This may eventually lead to oxidative stress whereby the increased level of free radicals may attack certain biomolecules (DNA, RNA, proteins lipids and carbohydrates) causing damage to cells, tissues and organs in the body. Following these attacks, certain by-products formed which are indicative of the cellular damage have been identified and considered as biomarkers for assessing oxidative stress. As such, assays have been developed to quantify these oxidative stress markers in body tissues, biological fluids, blood, urine samples etc. Oxidative stress has been associated with several diseases such as diabetes, atherosclerosis, hypertension, respiratory diseases, arthritis, cataract, cancer, cardiovascular diseases etc., as free radicals are implicated in the pathogenesis of these diseases. The antioxidant defense system collectively made up of enzymes and some low molecular weight molecules are usually suppressed in a state of oxidative stress and thus, external sources of antioxidant have been required to supplement the endogenous antioxidants. As such, antioxidant supplementation has been of interest in managing oxidative stress diseases. However, the use of antioxidant supplements remain controversial as some studies have shown possible harmful effects. Thus, there is need for further randomised clinical trials with defined and specified dosage that will make use of suitable controls and biomarkers for various diseases to better predict the efficacy of antioxidant supplements across a broad spectrum of diseases in order to valourise their usage.

Vascular Responses following Light Therapy: A Pilot Study with Healthy Volunteers.

(1) Background: Studies have reported the effectiveness of light therapy in various medical conditions. Our pilot study aimed to assess the effect of Maharishi light therapy (MLT) on physiological parameters, such as the heart rate (HR), HR variability (HRV), blood pressure (BP), BP variability (BPV), and the retinal microvasculature of healthy participants; (2) Methodology: Thirty (14 males and 16 females) healthy, non-smoking participants between 23 and 71 years old (46 ± 18 years) were included in this randomized crossover study. Each participant was tested with a placebo (using LED light) and gem lights, 24 h apart. Hemodynamic parameters were recorded during the session, and 24 h heart rate and BP levels were assessed via mobile devices. Retinal vascular responses were captured with fundus images and the subsequent analysis of retinal vessel widths. A linear model, using repeated measures ANOVA, was used to compare the responses across the sexes and to assess the effect of the MLT; (3) Results: Changes in the central retinal artery equivalent (CRAE) (p < 0.001) and central retinal vein equivalent (CRVE) (p = 0.002) parameters were observed. CRAE and CRVE decreased under MLT and increased under the placebo condition from before to after. However, the baseline values of the participants already differed significantly before the application of any therapy, and the variation in the retinal vessel diameters was already large in the baseline measurements. This suggests that the observed effect results may only reflect naturally occurring fluctuations in the microcirculation and not the effect of MLT. Furthermore, no significant effects were observed in any other investigated parameters; (4) Conclusion: Our study with healthy participants finds significant changes in retinal parameters, but the biological variation in the baseline measurements was large to begin with. This suggests that the observed effect results only reflect naturally occurring fluctuations in the microcirculation and not the effect of MLT. However, in the future, larger studies in which MLT is applied for longer periods and/or in patients with different diseases could discover the physiological impacts of this type of therapy.

Oxidative stress is associated with markers of renal dysfunction in children aged 6-9 years old in a South African population.

Introduction: although studies have shown a relationship between albuminuria and oxidative stress in adults, limited information on the subject is available in children. The aim of this study was to assess the relationship between oxidative stress and albuminuria in South African children of African ancestry. Methods: a cross-sectional study involving 6-9 years old children in randomly selected rural and urban schools of the Eastern Cape Province of South Africa was conducted. Anthropometric measurements were done and urine samples were collected for the determination of titres of albumin, creatinine, 8-hydroxy-2-deoxy-guanosine (8-OHdG) and thiobarbituric acid reactive substances (TBARS). The urinary albumin to creatinine ratio (ACR) was calculated and used to determine albuminuria. Results: creatinine and 8-OHdG were significantly higher (p<0.05) in urban children than in rural children while albumin, ACR and TBARS were significantly higher (p<0.05) in rural compared to urban children. The prevalence of albuminuria was 14.05% of which microalbuminuria was 8.83% while macroalbuminuria was 5.22%. Albuminuria was higher in rural children than their urban counterparts and was more prevalent in females. TBARS was positively (p<0.05) associated with creatinine and albumin in the cohort as well as in females and urban children while 8-OHdG was positively associated with albumin in the cohort. Conclusion: findings of this study showed that oxidative stress was associated with markers of renal dysfunction with a 14% prevalence of albuminuria observed in South African children of African ancestry.

Relationship between High Blood Pressure and Microalbuminuria in Children Aged 6-9 Years in a South African Population.

Though the association between high blood pressure and microalbuminuria is well established in adults, there is a paucity of information on microalbuminuria in children. This study investigated the relationship between high blood pressure and microalbuminuria in 6-9-year-old children. A cross-sectional study, which included 306 primary school children of age 6-9 years old from urban areas (n = 154) and rural areas (n = 152) of the Eastern Cape Province of South Africa, was conducted. Participants' anthropometric data were determined and systolic blood pressure (SBP), diastolic blood pressure (DBP) and heart rate (HR) were measured and converted to BP percentiles for age, sex and height. Creatinine and albumin concentrations were assayed in early morning midstream urine and the albumin to creatinine ratio (ACR) was calculated. There was a 42.8% prevalence of elevated blood pressure/high blood pressure (E-BP/H-BP) and a 10.1% prevalence of microalbuminuria. Among the 131 children with E-BP/H-BP, 17 had elevated ACR with a prevalence of 13.95%. SBP and HR increased with increasing range of ACR and, furthermore, SBP was significantly (p < 0.05) higher in children with moderately and severely increased ACR. SBP was associated with ACR and increased SBP predicted microalbuminuria (R2 = 0.42, adj R2 = 0.039, B: 0.120, p = < 0.05). In conclusion, microalbuminuria was present in 6-9-year-old South African children of African Ancestry and a weak association was observed with SBP in children.