Generation of active oxygens, cell deformation and membrane potential changes upon UV-B irradiation in human blood cells

Use of Ultraviolet Blood Irradiation Against Viral Infections

Ultraviolet blood irradiation (UBI) was used with success in the 1930s and 1940s for a variety of diseases. Despite the success, the lack of understanding of the detailed mechanisms of actions, and the achievements of antibiotics, phased off the use of UBI from the 1950s. The emergence of novel viral infections, from HIV/AIDS to Ebola, from SARS and MERS, and SARS-CoV-2, bring back the attention to this therapeutical opportunity. UBI has a complex virucidal activity, mostly acting on the immune system response. It has effects on lymphocytes (T-cells and B-cells), macrophages, monocytes, dendritic cells, low-density lipoprotein (LDL), and lipids. The Knott technique was applied for bacterial infections such as tuberculosis to viral infections such as hepatitis or influenza. The more complex extracorporeal photopheresis (ECP) is also being applied to hematological cancers such as T-cell lymphomas. Further studies of UBI may help to create a useful device that may find applications for novel viruses that are resistant to known antivirals or vaccines, or also bacteria that are resistant to known antibiotics.

Comparative In Vitro Study: Examining 635 nm Laser and 265 nm Ultraviolet Interaction with Blood

Objective: This study represents a viable assessment of the effect of the low-level laser (LLL) of 635 nm and ultraviolet (UV) of 265 nm on biophysical properties of blood. Materials and methods: Blood samples were divided into two main groups: one for irradiation by LLL and the other for irradiation by UV. Each group was divided into three aliquots. First aliquot: whole blood was exposed to radiation. The second aliquot: erythrocytes were exposed to radiation and resuspended in autologous plasma. The third aliquot: plasma was exposed to radiation, and erythrocytes were resuspended in it. The following parameters were measured after irradiation by LLL and UV for all aliquots: whole blood viscosity, microscopic aggregation index, deformation index, and Zeta potential. Results: A decrease in whole blood viscosity due to irradiation by LLL was observed. To the contrary, an increase in whole blood viscosity due to irradiation by UV was detected. A significant reduction in erythrocytes' aggregation was observed as a result of LLL and UV radiation. Erythrocytes' deformability was strongly affected by UV radiation, while there was no significant effect from LLL. Another noticeable change observed was an increase in Zeta potential due to UV and a decrease in Zeta potential values, as a result of LLL irradiation. Conclusions: It can be concluded from this study that LLL and UV can be used to change some biological processes, as well as cellular properties.

Ultraviolet Irradiation of Blood: "The Cure That Time Forgot"?

Ultraviolet blood irradiation (UBI) was extensively used in the 1940s and 1950s to treat many diseases including septicemia, pneumonia, tuberculosis, arthritis, asthma and even poliomyelitis. The early studies were carried out by several physicians in USA and published in the American Journal of Surgery. However with the development of antibiotics, UBI use declined and it has now been called "the cure that time forgot". Later studies were mostly performed by Russian workers and in other Eastern countries and the modern view in Western countries is that UBI remains highly controversial.This chapter discusses the potential of UBI as an alternative approach to current methods used to treat infections, as an immune-modulating therapy and as a method for normalizing blood parameters. No resistance of microorganisms to UV irradiation has been reported, and multi-antibiotic resistant strains are as susceptible as their wild-type counterparts. Low and mild doses of UV kill microorganisms by damaging the DNA, while any DNA damage in host cells can be rapidly repaired by DNA repair enzymes. However the use of UBI to treat septicemia cannot be solely due to UV-mediated killing of bacteria in the blood-stream, as only 5-7% of blood volume needs to be treated with UV to produce the optimum benefit. UBI may enhance the phagocytic capacity of various phagocytic cells (neutrophils and dendritic cells), inhibit lymphocytes, and oxidize blood lipids. The oxidative nature of UBI may have mechanisms in common with ozone therapy and other oxygen therapies. There may be some similarities to extracorporeal photopheresis (ECP) using psoralens and UVA irradiation. However there are differences between UBI and ECP in that UBI tends to stimulate the immune system, while ECP tends to be immunosuppressive. With the recent emergence of bacteria that are resistant to all known antibiotics, UBI should be more investigated as an alternative approach to infections, and as an immune-modulating therapy.

Molecular Aspects of Ultraviolet Radiation-Induced Apoptosis in the Skin

Background:

Apoptosis, or programmed cell death, is an essential physiological process that controls cell numbers during physiological processes, and eliminates abnormal cells that can potentially harm an organism.

Objective:

This review summarizes our current state of knowledge of apoptosis induction in skin by UV radiation.

Methods:

A review of the literature was undertaken focusing on cell death in the skin secondary to UV radiation.

Results:

It is evident that a number of apoptotic pathways, both intrinsic and extrinsic, are induced following exposure to damaging UV radiation.

Conclusion:

Although our understanding of the apoptotic processes is gradually increasing, many important aspects remain obscure. These include interconnections between pathways, wavelength-specific differences and cell type differences.

Ultraviolet blood irradiation: Is it time to remember "the cure that time forgot"?

Ultraviolet blood irradiation (UBI) was extensively used in the 1940s and 1950s to treat many diseases including septicemia, pneumonia, tuberculosis, arthritis, asthma, and even poliomyelitis. The early studies were carried out by several physicians in USA and published in the American Journal of Surgery. However, with the development of antibiotics, the use of UBI declined and it has now been called "the cure that time forgot." Later studies were mostly performed by Russian workers, and in other Eastern countries, and the modern view in Western countries is that UBI remains highly controversial. This review discusses the potential of UBI as an alternative approach to current methods used to treat infections, as an immune-modulating therapy and as a method for normalizing blood parameters. Low and mild doses of UV kill microorganisms by damaging the DNA, while any DNA damage in host cells can be rapidly repaired by DNA repair enzymes. However, the use of UBI to treat septicemia cannot be solely due to UV-mediated killing of bacteria in the bloodstream, as only 5-7% of blood volume needs to be treated with UV to produce the optimum benefit, and higher doses can be damaging. There may be some similarities to extracorporeal photopheresis (ECP) using psoralens and UVA irradiation. However, there are differences between UBI and ECP in that UBI tends to stimulate the immune system, while ECP tends to be immunosuppressive. With the recent emergence of bacteria that are resistant to all known antibiotics, UBI should be more investigated as an alternative approach to infections, and as an immune-modulating therapy.

Understanding loss of donor white blood cell immunogenicity after pathogen reduction: mechanisms of action in ultraviolet illumination and riboflavin treatment

BACKGROUND

Donor white blood cells (WBCs) present in transfusion products can lead to immune sequelae such as production of HLA antibodies or graft-versus-host disease in susceptible transfusion recipients. Eliminating the immunogenicity of blood products may prove to be of clinical benefit, particularly in patients requiring multiple transfusions in whom allosensitization is common. This study examines a method of pathogen reduction based on ultraviolet light illumination in the presence of riboflavin. In addition to pathogens, WBCs treated with this system are affected and fail to stimulate proliferation of allogeneic peripheral blood mononuclear cells (PBMNCs) in vitro.

STUDY DESIGN AND METHODS

This study sought to determine the mechanisms regulating this loss of immunogenicity. Treated cells were examined for surface expression of a number of molecules involved in activation and adhesion, viability, cell-cell conjugation, and ability to stimulate immune responses in allogeneic PBMNCs.

RESULTS

Compared with untreated controls, ultraviolet (UV)-irradiated antigen-presenting cells showed slightly reduced surface expression of HLA Class II and costimulatory molecules and had more significant reductions in surface expression of a number of adhesion molecules. Furthermore, treated cells had a severe defect in cell-cell conjugation. The observed loss of immunogenicity was nearly complete, with UV-irradiated cells stimulating barely measurable interferon-gamma production and no detectable STAT-3, STAT-5, or CD3-epsilon phosphorylation in allospecific primed T cells.

CONCLUSION

These results suggest that defective cell-cell adhesion prevents UV-irradiated cells from inducing T-cell activation.

Molecular Aspects of Ultraviolet Radiation-induced Apoptosis in the Skin

BACKGROUND

Apoptosis, or programmed cell death, is an essential physiological process that controls cell numbers during physiological processes, and eliminates abnormal cells that can potentially harm an organism.

OBJECTIVE

This review summarizes our current state of knowledge of apoptosis induction in skin by UV radiation.

METHODS

A review of the literature was undertaken focusing on cell death in the skin secondary to UV radiation.

RESULTS

It is evident that a number of apoptotic pathways, both intrinsic and extrinsic, are induced following exposure to damaging UV radiation.

CONCLUSION

Although our understanding of the apoptotic processes is gradually increasing, many important aspects remain obscure. These include interconnections between pathways, wavelength-specific differences and cell type differences.

Skin damage and mitochondrial dysfunction after acute ultraviolet B irradiation: relationship with nitric oxide production

BACKGROUND

Ultraviolet (UV) radiation is the main environmental carcinogen. It is able to induce injury in the keratinocytes, which triggers mechanisms in order to protect the skin against molecular alterations that may lead to the development of skin cancer. UVB is capable of producing genotoxic damage, directly or indirectly through reactive oxygen species, inducing DNA alterations and mutations. UVB radiation has also been associated with the generation of nitric oxide (NO), which is able to induce many physiological and physiopathological processes. The aim of the current study was to investigate the effect of UVB irradiation in hairless mice skin.

METHODS

We evaluated the effect of an acute dose (200 mJ/cm(2)) of UVB irradiation correlating with histological alterations, nitric oxide synthase expression and activity, mitochondrial respiratory function, superoxide anion production and lipid peroxidation, 0, 6, 17 and 24 h post-irradiation treatment.

RESULTS

Morphological analysis showed disruption of the epidermal stratum corneum and basale after UVB irradiation. The results indicated that skin UVB irradiation was associated with an increased cytosolic inducible nitric oxide synthase (iNOS) expression, inversely related to lipid peroxidation processes. An increase in mitochondrial superoxide anion (O(2) (*-)) and NO production 17 h post-irradiation was correlated with a mitochondrial dysfunction, all of them integrating the skin response to acute UVB irradiation.

CONCLUSIONS

UVB irradiation of the skin produces morphological alterations as a consequence of the induction of molecular mechanisms associated with mitochondrial respiratory dysfunction and O(2) (*-) production, probably mediated by the increased mitochondrial NO production. On the other hand lipid peroxidation decrease inversely correlates with cytosolic iNOS expression, suggesting a protective role for the inflammatory response.

Inactivation of pathogens in platelet concentrates by using a two-step procedure

BACKGROUND AND OBJECTIVES

Platelet concentrates are contaminated with residual leucocytes and may also be infected with viruses and bacteria. We investigated whether these pathogens can be inactivated by a two-step procedure comprising photodynamic treatment in the presence of the phenothiazine dye, thionine, followed by irradiation with ultraviolet light (UV-B, wavelength range 290-330 nm).

MATERIALS AND METHODS

Platelet concentrates were prepared from buffy coats. The concentrates were spiked with different viruses, bacteria and leucocytes, then illuminated with yellow light in the presence of thionine at dye concentrations between 1 and 5 microm and with UV-B at doses up to 2.4 J/cm2. The infectivity of samples and the viability of leucocytes were assayed before and after treatment. The influence of treatment on in vitro platelet function was also examined.

RESULTS

The inactivation of free viruses in platelet concentrates by photodynamic treatment with thionine/light was significantly enhanced when it was followed by irradiation with UV-B. The inactivation of leucocytes and of bacteria by UV-B was improved when it was preceded by thionine/light. Sterile platelet concentrates were prepared from buffy coats infected with Staphylococcus epidermidis. Platelet function and the storage stability of platelet concentrates were only moderately influenced by the two decontamination steps.

CONCLUSIONS

Photodynamic treatment in the presence of the phenothiazine dye, thionine, followed by low-dose UVB, has the potential to inactivate viruses, leucocytes and bacteria, which might contaminate platelet concentrates. Both treatments complement each other.

UV-B effects on Antarctic Chlorella sp cells

Growth of Antarctic Chlorella sp cells was measured in cultures irradiated with 30 kJ m(-2) UV-B (280-320 nm). The specific growth rate immediately after the lag phase was 0.36+/-0.06 and 0.26+/-0.03 day(-1) for unirradiated cultures and cultures irradiated with UV-B, respectively, UV-B irradiation significantly decreased ascorbate content by 54.5%, and increased the ascorbyl radical content/ascorbate content ratio by 2.25-fold in algae cultures in log phase. UV-B exposure significantly decreased by 95, 62 and 71% the content of alpha-tocopherol, beta-carotene and total thiols, respectively, in cells in log phase of development. The cellular content of alpha-tocopherol, beta-carotene and total thiols was reduced by 78, 43 and 44%, respectively in stationary phase, as compared to the antioxidant content in the cells during log phase of development. UV-B exposure reduced the content of alpha-tocopherol and total thiols in stationary phase of development by 64 and 91%, respectively, as compared to unirradiated cells. The content of beta-carotene in stationary phase was not affected by UV-B exposure. The results presented here suggest that increased UV-B radiation was responsible for the development of oxidative stress conditions, assessed as the ascorbyl radical content/ascorbate content ratio, in Antarctic Chlorella sp cells. Moreover, a significant decrease in the content of both lipid and water soluble antioxidants might contribute to establish oxidative stress in the cells.

Comparison of sensitivity to ultraviolet B irradiation between human lymphocytes and hematopoietic stem cells

To investigate the clinical applicability of prophylaxis of post-transplant graft-versus-host disease by UV-B irradiation of stem cell preparations, the UV-B sensitivities of human lymphocytes and primitive hematopoietic progenitors were compared. The mononuclear cell fractions (MNC) derived from human cord blood and granulocyte–colony-stimulating factor–mobilized peripheral blood were used. After UV-B irradiation, lymphocyte proliferation ability, hematopoietic colony-forming cells, and apoptotic cells were analyzed. At a dose of 33 J/m2, significant differences were observed in the residual percentages of hematopoietic progenitors and lymphocyte functions [ANOVA, F (5,46) = 19.4; P < .0001], and the difference between CFU-C (85.2% + 24.0%; n = 8) and MLR (12.7% + 12.6%; n = 10) was significant (P < .0001). There were no significant differences in the residual percentages of CFU-C, HPP-CFC, and LTC-IC. Percentages of annexin V-positive cells in the total MNC and the CD34+cell population in MNC after UV-B irradiation were 69.8% and 18.7%, respectively. In conclusion, there was a range of UV-B doses over which T lymphocytes were inactivated but hematopoietic progenitors, including HPP-CFC and LTC-IC, were preserved.

Comparison of sensitivity to ultraviolet B irradiation between human lymphocytes and hematopoietic stem cells

To investigate the clinical applicability of prophylaxis of post-transplant graft-versus-host disease by UV-B irradiation of stem cell preparations, the UV-B sensitivities of human lymphocytes and primitive hematopoietic progenitors were compared. The mononuclear cell fractions (MNC) derived from human cord blood and granulocyte–colony-stimulating factor–mobilized peripheral blood were used. After UV-B irradiation, lymphocyte proliferation ability, hematopoietic colony-forming cells, and apoptotic cells were analyzed. At a dose of 33 J/m2, significant differences were observed in the residual percentages of hematopoietic progenitors and lymphocyte functions [ANOVA, F (5,46) = 19.4; P < .0001], and the difference between CFU-C (85.2% + 24.0%; n = 8) and MLR (12.7% + 12.6%; n = 10) was significant (P < .0001). There were no significant differences in the residual percentages of CFU-C, HPP-CFC, and LTC-IC. Percentages of annexin V-positive cells in the total MNC and the CD34+cell population in MNC after UV-B irradiation were 69.8% and 18.7%, respectively. In conclusion, there was a range of UV-B doses over which T lymphocytes were inactivated but hematopoietic progenitors, including HPP-CFC and LTC-IC, were preserved.

Antioxidant adaptive response in human blood mononuclear cells exposed to UVB

Human blood mononuclear cells exposed to UVB radiation develop increased antioxidant enzyme activities. Catalase (5.50 +/- 0.65 pmol (mg protein)-1), CuZn-superoxide dismutase (16.7 +/- 2.1 pmol (mg protein)-1), Mn-superoxide dismutase (11.3 +/- 1.7 pmol (mg protein)-1), Se-dependent glutathione peroxidase (13.2 +/- 1.5 mU (mg protein)-1) and Se-independent glutathione peroxidase (3.30 +/- 0.52 mU (mg protein)-1) activities increase by 1.3-1.5-fold from the control activities after exposure to 0.3 W m-2 of 280-315 nm light for 15 min and a 3 h dark incubation period. DT-diaphorase activity (2.86 +/- 0.21 mumol DCPIP min-1 (mg protein)-1) increases threefold from the indicated control values. In contrast, cytochrome oxidase (0.36 +/- 0.04 min-1 (k') (mg protein)-1) and succinate dehydrogenase (3.06 +/- 0.25 mumol DCPIP min-1 (mg protein)-1) activities remain unchanged during the same irradiation and incubation period. The treatment of cells with cycloheximide prevents the response triggered by UVB exposure. These findings suggest that an inducible antioxidant defence mechanism operates on photo-oxidative stress and that both superoxide dismutase and DT-diaphorase may display a concerted antioxidant role.

Increased generation of hydrogen peroxide possibly from mitochondrial respiratory chain after UVB irradiation of murine fibroblasts

The purpose of this study is to detect the generation of active oxygens in UVB-irradiated murine fibroblasts and to propose new mechanisms. Decreased survival of fibroblasts under UVB irradiation was partially recovered by addition of catalase, DMSO or deferoxamine, suggesting the contribution of several types of active oxygen species. Then we examined the formation of active oxygen species and found that fibroblasts under UVB irradiation generated superoxide anion radicals (.O2-), intracellular H2O2, and hydroxyl radicals as estimated by the ESR-spin trapping method. Addition of thenoyltrifluoroacetone, which is an inhibitor of the mitochondrial respiratory chain, decreased 29% of the intracellular H2O2 levels in UVB-irradiated cells, but allopurinol, which is an inhibitor of xanthine oxidase, had no effect on them. On the basis of these results, we propose a a possible mechanism for damage of murine fibroblasts exposed to UVB in terms of generation of active oxygen species. The mitochondrial respiratory chain reaction stimulated by UVB irradiation enhances the generation of .O2-, which is in turn dismutated to H2O2 and O2 by superoxide dismutase. H2O2 is then converted to hydroxyl radicals, catalyzed by trace elements such as iron, as suggested by Fenton-like reaction. Thus, hydroxyl radicals with higher reaction rate-constants than those of other active oxygen species to biomolecules are indicated to be responsible for the cytotoxicity in cells under UV irradiation.

Slow fluorescent indicators of membrane potential: a survey of different approaches to probe response analysis

Basic tenets related to the use of three main classes of potentiometric redistribution fluorescent dyes (carbocyanines, oxonols, and rhodamines) are discussed in detail. They include the structure/function relationship, formation of nonfluorescent (H-type) and fluorescent (J-type) dimers and higher aggregates, probe partitioning between membranes and medium and binding to membranes and intracellular components (with attendant changes in absorption and emission spectra, fluorescence quantum yield and lifetime). The crucial importance of suitable probe-to-cell concentration ratio and selection of optimum monitored fluorescence wavelength is illustrated in schematic diagrams and possible artifacts or puzzling results stemming from faulty experimental protocol are pointed out. Special attention is paid to procedures used for probe-response calibration (potential clamping by potassium in the presence of valinomycin, use of gramicidin D in combination with N-methylglucamine, activation of Ca-dependent K-channels by A23187, the null-point technique). Among other problems treated are dye toxicity, interaction with mitochondria and other organelles, and possible effects of intracellular pH and the quantity of cytosolic proteins and/or RNA on probe response. Individual techniques using redistribution dyes (fluorescence measurements in cuvettes, flow cytometry and microfluorimetry of individual cells including fluorescence confocal microscopy) are discussed in terms of reliability, limitations and drawbacks, and selection of suitable probes. Up-to-date examples of application of slow dyes illustrate the broad range of problems in which these probes can be used.