Correlation between human health and reactive oxygen species produced in blood: a long-term chemiluminescence and fluorescence analysis.

The previous slide-glass type system could simultaneously detect reactive and highly reactive oxygen species, i.e., superoxide radicals (O2-·) and hypochlorite ions (OCl-) elicited from leucocytes in sample blood, but had some drawbacks, i.e., signal noise from air-flow stirring, potential biohazard risks, etc. because of open samples placed on a slide glass. We overcame these drawbacks by adopting a fluidic-chip container in a new system, which resulted in higher sensitivity and more stable measurements. Using the new system, we conducted a pilot study on nominally healthy volunteers to find whether or not the monitored activities of leukocytes can distinguish more or less unhealthy conditions from healthy ones. At first, healthy volunteers of both genders and of various ages showed that the fluctuation magnitudes (%) of O2-· and OCl- were nearly similar to each other and to that of the neutrophil count fluctuation. These parameters sometimes exceeded the healthy fluctuation range. By comparing these large fluctuations with the data of an inflammation marker C-reactive protein (CRP), the neutrophil count fluctuation and the timings/symptoms of abnormalities found in questionnaire, we could gain information suggesting the factors causing the large fluctuations. The new system could detect bodily abnormalities earlier than CRP or self-aware symptoms.

Rapid on-site dual optical system to measure specific reactive oxygen species (O2-• and OCl-) in a tiny droplet of whole blood.

Oxidative stress has been implicated in various disorders and controlling it would be important for healthy life. We have developed a new optical system for easily and accurately measuring oxidative stress in whole blood. It is optimized for simultaneously detecting reactive oxygen species (ROS) and highly reactive ROS (hROS), elicited mostly by white blood cells in a few microliters of blood. Results obtained by using this system show at least four important findings. 1) chemiluminescence of MCLA was confirmed to be attributable to O2-•. 2) PMA-stimulated cells released O2-• longer and more slowly than fMLP-stimulated ones. 3) fluorescence produced by APF oxidation was confirmed to be attributable to hROS, mostly OCl-, produced by myeloperoxidase. 4) the generation of OCl- was found to be a slower process than the O2-• generation. We also conducted pilot studies of oxidative stress in healthy volunteers.

Evaluation of a Hypertensive Rat Model Using Peripheral Blood Neutrophil Activity, Phagocytic Activity and Oxidized LDL Evaluation.

BACKGROUND/AIM: A system is being developed that can be used to easily evaluate the health condition of an individual with the help of trace amounts of a blood sample by focusing on xenobiotics. The system is called "Multimodal homeostasis evaluation system" (measurement of neutrophil activity, phagocytic activity of phagocytes and quantification of oxidized LDL (OxLDL)). To elucidate the possibility of using this system as an evaluation system for the health condition of an individual, clearly explaining the changes in various diseases is essential. In this study, evaluations were carried out using hypertensive model animals. MATERIALS AND METHODS: Spontaneously hypertensive model rats SHR/NCrlCrlj and control rats WKY/NCrlCrlj were raised for 10 weeks from 6 to 16 weeks of age and their blood pressure was measured over time. Blood neutrophil activity (superoxide anion (O2•-) generation and myeloperoxidase (MPO) activity) and phagocytic activity of phagocytes was measured by our developed apparatus (a simple prototype device under development). OxLDL was measured by an ELISA kit, and biochemical markers were measured using the blood sample. RESULTS: Compared to WKY rats of the control group, systolic blood pressure, diastolic blood pressure, and mean blood pressure of SHR rats increased significantly with age. In SHR rats, there was a significant elevation in O2•- generation and MPO activity of neutrophils, alanine aminotransferase and triglycerides of blood, while phagocytic activity, OxLDL, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, total cholesterol and total-bilirubin decreased. CONCLUSION: In the hypertensive model, biochemical markers were found to have a relationship with O2•- generation, MPO activity, phagocytic activity of phagocytes, and OxLDL. This system is expected to be useful for clinical monitoring of hypertension diseases.

Measurement of the Phagocytic Activity of Human Peripheral Blood Using a Highly Sensitive Fluorometric Detection Device Without Hemolysis.

BACKGROUND/AIM: Phagocytes recognize pathogens that enter the body as well as other abnormal and foreign materials that may exist within an organism (such as dead cells, oxidized lipids, and denatured proteins), and phagocytose and eliminate them to maintain a healthy state. In a previous study a simple prototype device was used, under development by Hamamatsu Photonics (Prototype), that detects fluorescence to determine the phagocytic activity of the murine macrophage cell line J774.1. The present study aimed to determine whether it was possible to detect phagocytic activity in a slight amount of human peripheral blood without using hemolysis. MATERIALS AND METHODS: Three microliters of human peripheral blood was drawn from the fingertip and mixed with 30 µg of pH-sensitive fluorescent particles. The fluorescence intensity of the human peripheral blood sample was then measured using the Prototype in development, cultured for 2 h at 37°C, and then re-measured. The phagocytes were observed under fluorescence microscopy and the phagocytosis rate of CD11b-positive cells was verified with a flow cytometer. RESULT: The phagocytic activity of non-hemolyzed human peripheral blood was measured using the Prototype under development; fluorescence after phagocytosis was detected. Furthermore, this was confirmed by both fluorescence microscopy and flow cytometry. The precision of the measurements of human peripheral blood phagocytic activity was verified with the Prototype using samples from three healthy individuals. The relationship between blood sugar levels and phagocytic activity before and after meal times was determined. Concerning exercise, phagocytic activity tended to decrease, although salivary amylase level increased in the healthy individual examined after exercise. CONCLUSION: The simple Prototype can measure phagocytic activity in a small amount of peripheral blood without hemolysis. The device allows for rapid and minimally-invasive detection of changes in phagocytic activity, which has conventionally been difficult. These findings provide promising evidence that assessment of individual phagocytic capacity can be made easier using this novel device.

Inhibition of neutrophil superoxide generation by shikonin is associated with suppression of cellular Ca(2+) fluxes.

Shikonin, an anti-inflammatory compound of "Shikon", inhibits the neutrophil superoxide (O2 (•-)) generation by NADPH oxidase 2 (Nox2); however, the mechanisms of how shikonin affects Nox2 activity remained unclear. We aimed to elucidate the relationship between the inhibition of Nox2 activity and influences on intracellular Ca(2+) concentration ([Ca(2+)]i) by shikonin. For this purpose, we used a simultaneous monitoring system for detecting changes in [Ca(2+)]i (by fluorescence) and O2 (•-) generation (by chemiluminescence) and evaluated the effects of shikonin on neutrophil-like HL-60 cells stimulated with N-formyl-l-methionyl-l-leucyl-l-phenylalanine (fMLP). Since fMLP activates Nox2 by elevation in [Ca(2+)]i via fluxes such as inositol 1,4,5-trisphosphate-induced Ca(2+) release (IICR) and store-operated Ca(2+) entry (SOCE), we also evaluated the effects of shikonin on IICR and SOCE. Shikonin dose-dependently inhibited the fMLP-induced elevation in [Ca(2+)]i and O2 (•-) generation (IC50 values of 1.45 and 1.12 µM, respectively) in a synchronized manner. Analyses of specific Ca(2+) fluxes showed that shikonin inhibits IICR and IICR-linked O2 (•-) generation (IC50 values: 0.28 and 0.31 µM for [Ca(2+)]i and O2 (•-), respectively), as well as SOCE and SOCE-linked O2 (•-) generation (IC50 values: 0.39 and 0.25 µM for [Ca(2+)]i and O2 (•-), respectively). These results suggested that shikonin inhibits the O2 (•-) generation by Nox2 in fMLP-stimulated neutrophils by targeting Ca(2+) fluxes such as IICR and SOCE.

Development of an Evaluation Device for Phagocytic Activity of New Phagocytes Using Simple and pH-sensitive Particles that Do Not Require Pre-treatment.

BACKGROUND/AIM: Phagocytic activity is affected by a number of different stress and age-dependent factors. An easy measurement of phagocytic activity is thought to allow an indicator of an individual's health. In this study, we investigated conditions of measurement to easily evaluate the activity of phagocytosis of phagocytic cells (macrophages and neutrophils) using an easy-to-use prototype, which was improved from the device by Hamamatsu Photonics K.K., to detect neutrophil activity using subtle fluorescence. MATERIALS AND METHODS: pH-sensitive fluorescent particles (pHrodo-Green E. coli Bio particles, GE particles) were added to mouse-derived macrophage cell lines (J774.1) and then incubated for 2 h at 37°C. For negative control, the phagocytosis inhibitor cytochalasin D (CyD), was added prior to culture. Next, fluorescence intensity was measured by the Prototype to evaluate the phagocytic activity of macrophages and neutrophils. Phagocytosis was also confirmed by flow cytometry. RESULTS: The Prototype detected a steady fluorescence increase in 5 sec in J774.1 after phagocytosis, using GE particles as a negative control in the presence of CyD. Furthermore, detection was possible at 10(4) cells/test, a concentration where the flow cytometer had difficulty for detection. CONCLUSION: The Prototype enables measurement of the phagocytic activity within a short period of time, even with a small sample amount, thus establishing the basic conditions of measurements of phagocytosis.