Light-Shielded Hemodialysis Prevents Hypotension and Lipid Peroxidation by Inhibiting Nitric Oxide Production

Abstract

Approximately 1 million patients with end stage renal disease are surviving throughout the world with the help of renal replacement therapy (1 ). More than 800 000 patients are currently receiving hemodialysis (HD), the most common modality. Survival on HD has progressively improved, although vascular accidents such as cerebral bleeding and ischemic heart disease continue to be major problems. One of the possible causes of the high incidence of vascular damage is thought to be a peroxidative condition in HD patients (2-4 ). HD treatment is usually performed in a bright room, using transparent blood circuitry for 4 h per session, 150 times per year. No attention has been paid, however, to the potential harm of these 600 h of exposure, although fluorescent light contains variable wavelengths, from ultraviolet to visible, that are known to generate reactive oxygen species after reacting with endogenous photodynamic reagents such as tryptophan or riboflavin (5 ). In this study, we investigated the effect of light shielding during HD on nitric oxide (NO) generation, blood pressure control, and lipid peroxidation in HD patients.The participants in this study were 10 stable HD patients. Their mean (SD) age was 48.1 (13.5) years, and the mean duration of HD was 8.2 (4.3) years. The cause of end stage renal failure was chronic glomerulonephritis in all patients. They were completely anuric and routinely dialyzed for 4 h, 3 times weekly. Over a period of 1 week, treatments alternated between ordinary HD and that in which the blood circuitry and the dialyzer were covered with aluminum foil (light-shielded HD). The dialysate used was bicarbonate-based, and the temperature was kept at 36.5°C. Blood pressure was measured every 30 min. Blood samples for the measurement of plasma concentrations of NO metabolites (NO 2 ϩ NO 3 ϭ NOx) were obtained every hour, and samples for plasma lipid peroxides were obtained at the start and end of HD. HD began around 1000 in the morning; none of the patients ate lunch during the HD session.Plasma NOx was measured by flow injection analysis based on the Griess reaction (6 ). For plasma lipid peroxides, we measured thiobarbituric acid-reactive substances (TBARS) and phosphatidylcholine hydroperoxide (PCOOH). TBARS were measured by the method of Ohkawa et al. (7 ). Separation of PCOOH by reversedphase HPLC was performed after the extraction of total plasma lipids according to the method of Bligh and Dyer (8 ), and quantification was by an ultraviolet detector at 235 nm and a chemiluminescence detector after the addition of luminol and cytochrome c (9).Values are expressed as the mean (SD). The time courses of plasma NOx concentrations during HD in both treatments were compared by 1-way ANOVA. The percentage changes in mean blood pressure, plasma TBARS, and PCOOH concentrations, comparing the end to the start in ordinary vs light-shielded HD, were calculated and analyzed by the paired t-test. Differences were considered significant at P Ͻ0.05.The results show that plasma NOx concentrations in sam...

A further review of the genetic and phenotypic nature of diabetes mellitus

“…Note 1: Light influences the function of a wide range of biochemicals and biological systems [20] e.g. it stimulates the release of nitric oxide (NO) [27][28][29][30][31] which is essential for smooth muscle function in the endothelium. Significantly, impaired NO metabolism is implicated in atherosclerosis, hypertension and diabetes.…”

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“…• it influences the production of Nitric Oxide [13,40] and subsequent regulation of blood pressure, lipid peroxidation, blood flow [41] and heart rate [42].…”

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“…Accordingly any factors which influence the function of the endocrines will inevitably influence blood pressure. In particular, light activates enzymes; stimulates the production of pituitary hormones by the pituitary gland and calcitriol by the skin; the production of Nitric Oxide[20] and the subsequent regulation of blood pressure and lipid peroxidation. Light is therefore an essential component in the body′s regulation.…”

“…it activates enzymes, which catalyse the body′s function[1819], and influences the (i) production of Nitric Oxide[20] and subsequent regulation of blood pressure and lipid peroxidation; (ii) migration of stem cells[21]; (iii) rate of wound healing[2223]; (iv) rate at which proteins translocate to the cell membrane[18]; (v) function of the lymphatic system[24]; (vi) regulation of intercellular pH balance[2526]; (vii) blood flow[27] and heart rate[28]; (viii) sperm motility[29]; (ix) sexual function[30]; (x) immune function[31–33], etc.…”