Differential Phagocytosis-Based Photothermal Ablation of Inflammatory Macrophages in Atherosclerotic Disease.

Inflammatory macrophage (Mφ)-mediated atherosclerosis is a leading cause of mortality and morbidity worldwide. Photothermal therapy (PTT) has been demonstrated as an efficient strategy in killing target cells, and its application in the treatment of inflammation in atherosclerosis is developing. However, the choice of nanomaterials, mechanisms, and side effects are seldom considered. In this study, semiconductor nanomaterials, that is, MoO2 nanoclusters, were synthesized and used for the first time in PTT for inflammatory Mφ-mediated atherosclerosis. Based on cell differential phagocytosis, the optimum amount of MoO2 and treatment time were selected to exert the maximum ablation effect on Mφ and minimal damage on endothelial cells without requiring additional target or selective groups. Moreover, MoO2-based PTT shows an excellent therapeutic effect on atherosclerosis by eliminating Mφ in animal models, with no significant side effects observed. This study explores a new method of nanotechnology and pharmaceutical development by using and optimizing cost-effective metal oxide nanostructures in the treatment of atherosclerosis and motivates further research on minimizing the side effects of related materials.

Photo-enhancement of macrophage phagocytic activity via Rac1-mediated signaling pathway: Implications for bacterial infection.

Phagocytosis and the subsequent destruction of invading pathogens by macrophages are indispensable steps in host immune responses to microbial infections. Low-power laser irradiation (LPLI) has been found to exert photobiological effects on immune responses, but the signaling mechanisms underlying this photobiomodulation of phagocytosis remains largely unknown. Here, we demonstrated for the first time that LPLI enhanced the phagocytic activity of macrophages by stimulating the activation of Rac1. The overexpression of constitutively activated Rac1 clearly enhanced LPLI-induced phagocytosis, whereas the overexpression of dominant negative Rac1 exerted the opposite effect. The phosphorylation of cofilin was involved in the effects of LPLI on phagocytosis, which was regulated by the membrane translocation and activation of Rac1. Furthermore, the photoactivation of Rac1 was dependent on the Src/PI3K/Vav1 pathway. The inhibition of the Src/PI3K pathway significantly suppressed LPLI-induced actin polymerization and phagocytosis enhancement. Additionally, LPLI-treated mice exhibited increased survival and a decreased organ bacterial load when challenged with Listeria monocytogenes, indicating that LPLI enhanced macrophage phagocytosis in vivo. These findings highlight the important roles of the Src/PI3K/Vav1/Rac1/cofilin pathway in regulating macrophage phagocytosis and provide a potential strategy for treating phagocytic deficiency via LPLI.

Photobiomodulation with 670 nm light increased phagocytosis in human retinal pigment epithelial cells.

PURPOSE: Photobiomodulation is the treatment with light in the far-red to near-infrared region of the spectrum and has been reported to have beneficial effects in various animal models of disease, including an age-related macular degeneration (AMD) mouse model. Previous reports have suggested that phagocytosis is reduced by age-related increased oxidative stress in AMD. Therefore, we investigated whether photobiomodulation improves phagocytosis caused by oxidative stress in the human retinal pigment epithelial (ARPE-19) cell line. METHODS: ARPE-19 cells and human primary retinal pigment epithelium (hRPE) cells were incubated and irradiated with near-infrared light (670 nm LED light, 2,500 lx, twice a day, 250 s/per time) for 4 d. Next, hydrogen peroxide (H2O2) and photoreceptor outer segments (POS) labeled using a pH-sensitive fluorescent dye were added to the cell culture, and phagocytosis was evaluated by measuring the fluorescence intensity. Furthermore, cell death was observed by double staining with Hoechst33342 and propidium iodide after photobiomodulation. CM-H2DCFDA, JC-1 dye, and CCK-8 were added to the cell culture to investigate the reactive oxygen species (ROS) production, mitochondrial membrane potential, and cell viability, respectively. We also investigated the expression of phagocytosis-related proteins, such as focal adhesion kinase (FAK) and Mer tyrosine kinase (MerTK). RESULTS: Oxidative stress inhibited phagocytosis, and photobiomodulation increased the oxidative stress-induced hypoactivity of phagocytosis in ARPE-19 cells and hRPE cells. Furthermore, H2O2 and photobiomodulation did not affect cell death in this experimental condition. Photobiomodulation reduced ROS production but did not affect cell viability or mitochondrial membrane potential. The expression of phosphorylated MerTK increased, but phosphorylated FAK was not affected by photobiomodulation. CONCLUSIONS: These findings indicate that near-infrared light photobiomodulation (670 nm) may be a noninvasive, inexpensive, and easy adjunctive therapy to help inhibit the development of ocular diseases induced by the activation of phagocytosis.

Docosahexaenoic acid aggravates photooxidative damage in retinal pigment epithelial cells via lipid peroxidation.

Docosahexaenoic acid (DHA, 22:6n-3), a long-chain polyunsaturated fatty acid (PUFA) with important functions in normal human retinal activity and vision development, is recommended to promote brain and eye development. However, recent research has revealed that increased DHA level in the retina due to linoleic acid-rich diet heightens the vulnerability of the retina to photooxidative stress. Thus, many scholars have analyzed the potential risks of DHA intake on retinal damage. This study evaluated the potential adverse effects of DHA intake on individuals usually exposed to high-light intensity conditions using a visible light-induced retinal pigment epithelium (RPE) cell damage model in vitro. Results showed that DHA promoted the proliferation of RPE cells without any cytotoxicity under dark conditions. However, DHA supplement elicited deleterious effects on RPE cells under high-intensity light conditions. That is, DHA supplement inhibited cellular proliferation, destroyed cell membrane integrity, enhanced cellular senescence, increased vascular endothelial growth factor (VEGF) release, and decreased phagocytic function. Moreover, DHA supplement increased the intracellular and extracellular levels of reactive oxygen species and the extracellular level of lipid peroxidation products under high-intensity light conditions. These results demonstrate that DHA increases the vulnerability of the retina to light damage through lipid peroxidation.

Low-level laser therapy regulates microglial function through Src-mediated signaling pathways: implications for neurodegenerative diseases.

BACKGROUND: Activated microglial cells are an important pathological component in brains of patients with neurodegenerative diseases. The purpose of this study was to investigate the effect of He-Ne (632.8 nm, 64.6 mW/cm2) low-level laser therapy (LLLT), a non-damaging physical therapy, on activated microglia, and the subsequent signaling events of LLLT-induced neuroprotective effects and phagocytic responses. METHODS: To model microglial activation, we treated the microglial BV2 cells with lipopolysaccharide (LPS). For the LLLT-induced neuroprotective study, neuronal cells with activated microglial cells in a Transwell™ cell-culture system were used. For the phagocytosis study, fluorescence-labeled microspheres were added into the treated microglial cells to confirm the role of LLLT. RESULTS: Our results showed that LLLT (20 J/cm2) could attenuate toll-like receptor (TLR)-mediated proinflammatory responses in microglia, characterized by down-regulation of proinflammatory cytokine expression and nitric oxide (NO) production. LLLT-triggered TLR signaling inhibition was achieved by activating tyrosine kinases Src and Syk, which led to MyD88 tyrosine phosphorylation, thus impairing MyD88-dependent proinflammatory signaling cascade. In addition, we found that Src activation could enhance Rac1 activity and F-actin accumulation that typify microglial phagocytic activity. We also found that Src/PI3K/Akt inhibitors prevented LLLT-stimulated Akt (Ser473 and Thr308) phosphorylation and blocked Rac1 activity and actin-based microglial phagocytosis, indicating the activation of Src/PI3K/Akt/Rac1 signaling pathway. CONCLUSIONS: The present study underlines the importance of Src in suppressing inflammation and enhancing microglial phagocytic function in activated microglia during LLLT stimulation. We have identified a new and important neuroprotective signaling pathway that consists of regulation of microglial phagocytosis and inflammation under LLLT treatment. Our research may provide a feasible therapeutic approach to control the progression of neurodegenerative diseases.

Polysaccharide extracted from Rheum tanguticum prevents irradiation-induced immune damage in mice.

AIM: To investigate the protective effect of purified fraction 1 polysaccharide extracted from Rheum tanguticum RTP1 on irradiation-induced immune damage in mice. METHODS: Kunming mice were randomly divided into five groups: normal group (NC), irradiation control group (IC), RTP1 low dose (200 mg/kg), middle dose (400 mg/kg) and high dose (800 mg/kg) groups. RTP1 was administered by the gastric route for 14 d, mice in the NC and IC groups being given by 0.9% sodium chloride solution in the same way. The mice in all groups except NC group were irradiated with 2.0 Gy6°Co γ-ray on the fourteenth day. Immune indives of non-specific immune function, cellular immunity and humoral immunity were assessed at the 24th hour after radiation. RESULTS: Compared with the IC group, the spleen index, thymus index, rate of carbon clearance, phagocytic function of macrophages, lymphocyte proliferation, hemolysin value of blood serum and NK activity were increased markedly (P < 0.05 or P < 0.05). CONCLUSION: RTP1 has an obvious protective effects on damage in γ-ray radiated mice.

[Analysis of parameters of reproductive tract mucosal immunity in women with chlamydial infection before and after local magnetolaserotherapy].

The objective of the present study was to evaluate the influence of combined treatment with low-intensity laser radiation and magnetic field on neutrophil function in women presenting with Chlamydial infection. Dysfunction of neutrophil granulocytes in these patients was manifest in the first place as the decreased number of phagocytes and the low rate of phagocytosis. It was shown that the concentration of active oxygen species in neutrophils in the patients with Chlamydial infection was significantly smaller than in healthy women. The concurrent application of low-intensity laser radiation and a magnetic field not only stimulated phagocytosis but also increased intracellular production of active oxygen species especially under in vitro conditions. It is concluded that combined treatment with low-intensity laser radiation and magnetic field has beneficial effect on the parameters of mucosal immunity in the reproductive tract of women with Chlamydial infection.

[Low-intensity laser effects on local immunity of female reproductive system affected with chlamidia infection].

Low-intensity laser impact on the main effector functions of the cervical secretion neutrophils in females suffering from Chlamidia infection has been studied. Dysfunction of neutrophil granulocytes of the cervical secretion was revealed. This manifested in the decreased number of phagocytes and lower rates of phagocytosis. The study of cervical secretion neutrophils has found that the content of active intracellular forms of oxygen was decreased in patients compared to healthy subjects. Low-intensity laser stimulated not only phagocytosis but also intracellular generation of active oxygen forms. Thus, low-intensity laser eliminates dysfunction of cervical secretion neutrophils.

[State of humoral immunity and phagocytic activity of neutrophils in patients with ulcer and effect of low-intensity laser therapy]. / Sostoianie gumoral'nogo immuniteta i fagotsitarnoi aktivnosti neitrofilov u bol'nykh iazvennoi bolezn'iu i vliianie na nikh nizkointensivnoi lazernoi terapii.

The aim of our investigation was to study the influence of low-intensity laser therapy at the immunologic parameters and Helicobacter pylori (HP) microbial contamination in patients with exacerbation of peptic and duodenal ulcer. 100 patients aged 18-65 were examined and divided into 2 groups. The experimental group (75 patients) underwent a complex drug and laser therapy of various therapeutic techniques. The control group (25 patients) underwent only drug therapy. The results of this study show the immunocorrective effect of different methods of low-intensity laser therapy in the exacerbation period and more essential decrease of HP microbial contamination in the experimental group.

[A combined method for wound treatment based on low intensity irradiation and ultrasound ]. / Kombinirovannyi metod lecheniia ran na osnove nizkointensivnogo izlucheniia i ul'trazvuka.

A new combined photoultrasonic technique is suggested for the treatment of infectious injuries. The experiments were implemented on 70 male chinchilla rabbits (7 groups). The dynamics and nature of injuries' healing were analyzed by clinical pathomorphological and histochemical data as well as by biopsy samplings and capillaroscopy of injuries' edges. The experimental results of animals' models demonstrated a high efficiency of the combined photoultrasonic treatment as applicable to the above injuries.

[The efficacy of the transcutaneous magnetic-laser irradiation of the blood in acute salpingo-oophoritis]. / Effektivnost' chreskozhnogo magnitno-lazernogo oblucheniia krovi pri ostrykh sal'pingooforitakh.

The effect of including transcutaneous low-intensity magnetic-laser radiation of blood in combined antiinflammatory therapy of salpingo-oophoritis was studied. This physiotherapy stimulates phagocytic activity of neutrophilic leukocytes of the peripheral blood, promotes faster normalization of enzymatic and non-enzymatic systems of these cells.

Ultraviolet-irradiated monocytes efficiently inhibit the intracellular replication of Mycobacterium avium intracellulare.

The purpose of this study was to evaluate the effect of ultraviolet (UV) radiation on the antimicrobial activities of monocytes for the intracellular pathogen Mycobacterium avium intracellulare (MAI). UV radiation augmented monocyte antimicrobial activity for MAI in a dose-dependent fashion. UVB doses of greater than or equal to 25 J/m2 resulted in a 50-100-fold reduction in MAI growth 7 d after initiation of culture. The increased monocyte antibacterial effect could be blocked by a plate glass filter, indicating that wavelengths within the UVB were responsible for the effect. UV radiation did not stimulate monocyte phagocytosis, and enhanced inhibition of MAI growth was observed in populations of adherent mononuclear cells that were devoid of T cells. This suggested that UV radiation acted directly to augment intrinsic monocyte antimicrobial activities. The administration of 8-methoxypsoralen plus UVA radiation to monocytes also augmented their antimicrobial activities against MAI. UV radiation thus may serve as a unique agent by which to evaluate the mechanisms by which mononuclear phagocytes control the growth of MAI.

[Changes in the surface and activation of circulating leukocytes after autologous transfusion of UV-irradiated blood]. / Izmeneniia poverkhnosti i aktivatsii tsirkuliruiushchikh leikotsitov pri autotransfuziiakh UF-obluchennoi krovi.

Under study was the dynamics of functional properties of leukocytes of healthy people and patients after UV-irradiation of their blood, mixing the UV-irradiated and non-irradiated blood. It was shown that UV-irradiation and mixing the irradiated and non-irradiated blood facilitated the liberation of bactericidal cation proteins of leukocytes, higher expression of membrane receptors, growth factors, activation of reparation of DNA after its injury by gamma-rays. It proves the role of immediate activation of leukocytes of the circulating blood in trigger mechanisms of effects of autotransfusion of UV-irradiated blood.

[Systemic effects of ultraviolet, visible and infrared radiation in serial whole body irradiation. I. Oxygen utilization, flow properties of blood, hemodynamics, blood components and phagocytosis]. / Systemische Effekte der Ultraviolett-, sichtbaren bzw. Infrarotstrahlung bei seriellen Ganzkörperbestrahlungen. I. Sauerstoffutilisation, Fliesseigenschaften des Blutes, Hämodynamik, Blutbestandteile und Phagozytose.

31 healthy volunteers at the age of 19 to 29 years underwent whole-body irradiations by either ultraviolet radiation (NARVA UVS 65-2; continuous sunshine-like emission, predominantly UVA plus 8% UVB; cumulative doses after 4 and 20 irradiations 8.8 J/cm2 and 51.0 J/cm2, respectively), or visible light (emission of a 3,500 Watt lamp HGMI 3500 DL, Tungsram CSSR, filtered through 6 mm window glass; cumulative dose 267.0 J/cm2 after 4 irradiations) or infrared radiation (250 Watt infrared lamps NARVA "Biotherm", emitting more than 70% infrared radiation; cumulative dose 159.0 J/cm2 after 4 irradiations). Before, during and after the irradiation series the following investigations were made: Arterial and venous oxygen pressure, oxygen utilization index; flow properties of peripheral blood (plasma viscosity, erythrocyte aggregation kinetics, apparent blood viscosity); hemodynamics (veineal plethysmography, 133Xenon clearance, functional diameter of small blood vessels, peripheral blood pressure), phagocytotic capacity of polymorphonuclear white blood cells; hematological parameters (blood sedimentation rate, polymorphonuclear and eosinophilic blood cells, red blood cells, hemoglobin, hematocrit), serum proteins (IgG, IgA, IgM, complement C3, alpha-1-glycoprotein, alpha-1-antitrypsin, haptoglobin, transferrin); calcium and phosphate in serum. As far as irradiance, dose and treatment frequencies are concerned, the experimental conditions were very similar to those in phototherapeutical practice. Under these circumstances there were no hints for unwanted early effects after application of all the three kinds of optical radiation used in that study. Considerable systemic responses exclusively were found by use of ultraviolet radiation. Under these experimental conditions according to dermatological phototherapy it has been proven the following biopositive systemic responses are due to happen: increase of serum calcium and phosphate, improvement of blood oxygen utilization, improvement of blood flow properties, and enhanced phagocytic capacity of polymorphonuclear white blood cells. Regarding the parameters taken in that study, no early unwanted side effects are to expect after therapeutical application of rather large doses of visible light or infrared radiation.

[Effect of ultraviolet irradiation of autologous blood on cell volumes, cell adhesion and phagocytosis in normal probands and patients with multiple sclerosis]. / Einfluss von Ultraviolettbestrahlung des Blutes (UVB) auf Zellvolumen, Zelladhärenz und Phagozytose bei Normalprobanden und Patienten mit Multipler Sklerose (MS).

UVB induced changes of blood cell properties were investigated in 12 MS patients and in 10 healthy volunteers serving as normal controls. The mean cell volume (MCV) was determined by electronic sizing, the granulocyte and lymphocyte adherence was estimated in a capillary assay, and the phagocytic activity of granulocytes was measured in a test system based on the incorporation of opsonized baker's yeast (Saccharomyces cerevisiae). In MS patients the MCV of red cells and lymphocytes decreased rapidly within 6 UVB treatments. In contrast, the reduction of the granulocyte volume was delayed (between the 6th and 12th UVB). In the control group the mean value of the red cell and lymphocyte MCV remained rather unaffected. There was a slight rise of the granulocyte volume after the 6th UVB. The only significant change of adherence was an increase of granulocyte adherence in MS patients. Untreated patients had a significantly enhanced phagocytic activity in comparison to the control group. 6 UVB treatments included a significant reduction of the phagocytic activity in MS patients. However, subsequently the percentage of phagocytizing cells increased again, whereas the particle uptake per cell continued to decrease. In the control group only minor UVB induced changes of phagocytosis were observed. The in vitro UV irradiation caused an enhanced phagocytosis in the majority of cases in both controls and MS patients. In general, under the UVB treatment all parameters examined changed in the sense of a normalisation, in that the measured values reached a new level lying between the extreme pretreatment values accompanied by a reduced standard deviation. The effect of UVB was more pronounced in MS patients when compared with normal controls. This could result from an enhanced sensitivity to the influence of UVB of pathologically altered cells in MS patients. The monitoring of the MCV of red cells and lymphocytes as well as the repeated testing of granulocyte phagocytosis are recommended for supportion of therapy planning and follow-up of MS patients.

[Changes in the leukocyte phagocytic activity of donor blood after its UV irradiation. II. Simulation of the effect of the autotransfusion of UV-irradiated blood]. / Izmenenie fagotsitarnoi aktivnosti leikotsitov donorskoi krovi posle ee UF-oblucheniia. II. Modelirovanie éffekta autotransfuzii UF-obluchennoi krovi.

The UV-irradiated blood of healthy adults was supplemented with non-irradiated blood in the ratio 1:10. The phagocytic activity (PhA) of monocytes and granulocytes was seen to increase markedly in the whole mixture of blood. In this case the rise of PhA was pronounced 1.4-1.7 times as much as in the case of the non-supplemented, directly UV-irradiated blood. The enhancement of PhA depends on its initial level and may occur simultaneously with structural changes of the cell surface components. It seems reasonable to propose that PhA stimulation may be one of the earliest mechanisms in immunocorrection by UV-irradiated blood therapy.

[Changes in the leukocyte phagocytic activity of donor blood after its UV irradiation. I. Its relation to the irradiation dose and initial level of phagocytic activity]. / Izmenenie fagotsitarnoi aktivnosti leikotsitov donorskoi krovi posle ee UF-oblucheniia. I. Zavisimost' ot dozy oblucheniia i iskhodnogo urovnia fagotsitarnoi aktivnosti.

Phagocytic activity of human mono- and granulocytes increased markedly after UV blood irradiation in the apparatus "Izolda" used in hospitals of the USSR for medical treatment. With the rise of irradiation dose the ratio of cells ingesting latex particles increased, although the average number of particles ingested per cell decreased. The integrative phagocytic index poorly depended on the irradiation dose. In patients with a low initial level of phagocytic index, after UV blood irradiation it became more pronounced than in those with the initial elevated level. The enhancement of phagocytic activity is the result of a direct UV-stimulation of cells. This stimulation not mediated by irradiated blood plasma is known to inhibit the phagocytic activity of leucocytes. A possible mechanism of phagocytic activity stimulation is discussed.