Irradiation Causes Biphasic Neutrophilic Granulocyte Phagocytic Function*

PKCδ inhibition as a novel medical countermeasure for radiation-induced vascular damage

In the event of a radiologic catastrophe, endothelial cell and neutrophil dysfunction play important roles in tissue injury. Clinically available therapeutics for radiation-induced vascular injury are largely supportive. PKCδ was identified as a critical regulator of the inflammatory response, and its inhibition was shown to protect critical organs during sepsis. We used a novel biomimetic microfluidic assay (bMFA) to interrogate the role of PKCδ in radiation-induced neutrophil-endothelial cell interaction and endothelial cell function. HUVECs formed a complete lumen in bMFA and were treated with 0.5, 2, or 5 Gy ionizing radiation (IR). At 24 h post-IR, the cells were treated with a PKCδ inhibitor for an additional 24 h. Under physiologic shear flow, the role of PKCδ on endothelium function and neutrophil adherence/migration was determined. PKCδ inhibition dramatically attenuated IR-induced endothelium permeability increase and significantly decreased neutrophil migration across IR-treated endothelial cells. Moreover, neutrophil adhesion to irradiated endothelial cells was significantly decreased after PKCδ inhibition in a flow-dependent manner. PKCδ inhibition downregulated IR-induced P-selectin, intercellular adhesion molecule 1, and VCAM-1 but not E-selectin overexpression. PKCδ is an important regulator of neutrophil-endothelial cell interaction post-IR, and its inhibition can serve as a potential radiation medical countermeasure.-Soroush, F., Tang, Y., Zaidi, H. M., Sheffield, J. B., Kilpatrick, L. E., Kiani, M. F. PKCδ inhibition as a novel medical countermeasure for radiation-induced vascular damage.

Radiotherapy in langerhans cell histiocytosis - a rare indication in a rare disease

Introduction

Langerhans Cell Histiocytosis (LCH) represents a rare benign disorder, previously designated as “Histiocytosis X”, “Type II Histiocytosis” or “Langerhans Cell Granulomatosis”. Clinical presentation includes osteolysis, ulcerations of skin and soft tissues but also involvement of the CNS is described.

Because treatment concepts are not well defined the German Cooperative Group on Radiotherapy for Benign Diseases performed a retrospective analysis.

Methods and material

Eight closely cooperating centres collected patients’ data of the past 45 years. As study endpoints disease free survival, recurrent disease, death and therapy related side effects were defined.

Results

A total of 80 patients with histologically proven LCH were irradiated within the past 45 years. According to the LCH classification of Greenberger et al. 37 patients had stage Ia, 21 patients stage Ib, 13 patients stage II and 9 patients stage IIIb and the median age was 29 years. The median Follow up was 54 months (range 9–134 months). A total of 39 patients had a surgical intervention and 23 patients a chemotherapy regimen.

Radiation treatment was carried out with a median total dose of 15 Gy (range 3–50.4 Gy). The median single fraction was 2 Gy (range 1.8-3 Gy).

Overall, 77% patients achieved a complete remission and 12.5% achieved a partial remission. The long-term control rate reached 80%. Within an actuarial overall 5-year survival of 90% no radiogenic side and late effects ≥EORTC/RTOG II° were observed.

Conclusion

In the present study a large collective of irradiated patients was analysed. Radiotherapy (RT) is a very effective and safe treatment option and even low RT doses show sufficient local control.

Low dose ionising radiation leads to a NF-κB dependent decreased secretion of active IL-1β by activated macrophages with a discontinuous dose-dependency

PURPOSE

Therapy with low doses of ionising radiation (X-rays) exerts anti-inflammatory effects. Little is known about whether and how low doses of X-ray treatment modulate the inflammatory phenotype of macrophages, especially the secretion of Interleukin-1beta (IL-1β).

MATERIALS AND METHODS

Macrophages were differentiated from human THP-1 monocytes, activated with lipopolysaccharide (LPS), treated with distinct low doses of X-rays, and co-activated with monosodium urate crystals (MSU) to induce inflammasome activation. Secretion of IL-1β was analysed by an enzyme-linked immunosorbent assay (ELISA) and Western blot. Furthermore, we analysed the intracellular amounts of the serine/threonine protein kinase B (named: Akt), mitogen-activated protein kinase p38 (p38), the v-rel reticuloendotheliosis viral oncogene homolog A (RelA), and pro- and cleaved IL-1β.

RESULTS

Low dose X-rays led to decreased secretion of active IL-1β in a manner discontinuous with dose which was most pronounced after 0.5 or 0.7 Gy. Passive release of lactate dehydrogenase (LDH) was not influenced by X-rays. The decreased secretion of IL-1β correlated with reduced translocation of RelA, being part of the nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) complex, into the nucleus. After 0.5 or 0.7 Gy of X-rays, the intracellular protein amounts of up (p38) and downstream molecules (Akt) of NF-κB were reduced in activated macrophages, as were the pro- and cleaved forms of IL-1β.

CONCLUSIONS

Distinct low doses of X-rays induce an anti-inflammatory phenotype of activated macrophages by lowering the amount of secreted IL-1β in a NF-κB dependent manner.

Radioprotective effects of black seed (Nigella sativa) oil against hemopoietic damage and immunosuppression in gamma-irradiated rats

BACKGROUND AND AIM

Sixty male Wistar rats, divided into 4 groups, 15 each, were designed as I-control rats, II-rats orally intubated with Nigella sativa oil (1 ml/kg b.wt./day) for 5 days/week, III-whole body gamma irradiated rats with the estimated LD50/30 (4 Gray) and IV-rats daily intubated with Nigella sativa oil then subjected to whole body gamma irradiation, to investigate the radioprotective potential of Nigella crude oil against hemopoietic adverse effects of gamma irradiation.

RESULTS

Irradiation resulted in significant reduction in hemolysin antibodies titers and delayed type hypersensitivity reaction of irradiated rats, in addition to significant leukopenia and significant decrease in plasma total protein and globulin concentrations and depletion of lymphoid follicles of spleen and thymus gland. Furthermore, there was a significant increase in malondialdehyde concentration with a significant decrease in plasma glutathione peroxidase, catalase and erythrocyte superoxide dismutase activities were recorded. Oral administration of Nigella sativa oil before irradiation considerably normalized all the above-mentioned criteria; and produced significant regeneration in spleen and thymus lymphoid follicles.

CONCLUSION

Our results strongly recommend Nigella sativa oil as a promising natural radioprotective agent against immunosuppressive and oxidative effects of ionizing radiation.

Activation-induced cell death and total Akt content of granulocytes show a biphasic course after low-dose radiation

Low-dose radiation (single doses from 0.3 to 1.0 Gy) in clinical practice is mostly used to treat patients with several inflammatory diseases and painful degenerative disorders. Low-dose radiation is known to exert anti-inflammatory effects. However, the molecular and cellular mechanism are not fully analysed and most of the observed effects are based on empirical studies. We investigated the effects of low-dose radiation on the activation-induced cell death of polymorph nuclear granulocytes (PMN). A biphasic appearance of cell death in irradiated PMN was observed, displaying a relative maximum at 0.3 Gy and minimum at 0.5 Gy, respectively. This biphasic course of cell death was coincident with the protein level of total cellular Akt. We conclude that low-dose radiation exerts immunomodulatory effects on PMN contributing to the observed anti-inflammatory effects in clinical applications.

Demographic, clinical and treatment related predictors for event-free probability following low-dose radiotherapy for painful heel spurs - a retrospective multicenter study of 502 patients

A total of 502 patients treated between 1990 and 2002 with low-dose radiotherapy (RT) for painful heel spurs were analysed for prognostic factors for long-term treatment success. The median follow-up was 26 months, ranging from 1 to 103 months. Events were defined as (1) slightly improved or unchanged pain after therapy, or (2) recurrent pain sensations during the follow-up period. Overall 8-year event-free probability was 60.9%. Event-free probabilities of patients with one/two series (414/88) were 69.7%/32.2% (p<0.001); >58/ < or = 58 years (236/266), 81.3%/47.9% (p=0.001); high voltage/orthovoltage (341/161), 67.9%/60.6% (p=0.019); pain anamnesis < or = 6 months/ >6 months (308/194), 76.3%/43.9% (p=0.001); single dose 0.5/1.0 Gy (100/401), 86.2%/55.1% (p=0.009); without/with prior treatment (121/381), 83.1%/54.9% (p=0.023); men/women (165/337), 61.2%/61.5% (p=0.059). The multivariate Cox regression analysis with inclusion of the number of treatment series, age, photon energy, pain history, single-dose and prior treatments revealed patients with only one treatment series (p<0.001), an age >58 years (p=0.011) and therapy with high voltage photons (p=0.050) to be significant prognostic factors for pain relief. Overall low-dose RT is a very effective treatment in painful heel spurs.

Radiobiological mechanisms in inflammatory diseases of low-dose radiation therapy

PURPOSE

Whereas X-irradiation with high doses is established to exert pro-inflammatory effects, low-dose radiotherapy (LD-RT) with single fractions below 1.0 Gy and a total dose below 12 Gy is clinically well known to exert anti-inflammatory and analgesic effects on several inflammatory diseases and painful degenerative disorders. Experimental studies to confirm the effectiveness, the empirical dose and fractionation schemes, and the underlying radiobiological mechanisms are still fragmentary.

METHOD

The anti-inflammatory efficiency of LD-RT was confirmed in several experimental in vitro and in vivo models.

RESULTS

In vitro studies revealed a variety of mechanisms related to the anti-inflammatory effect, in particular the modulation of cytokine and adhesion molecule expression on activated endothelial cells and leukocytes, and of nitric oxide (NO) production and oxidative burst in activated macrophages and native granulocytes.

CONCLUSION

Inflammatory diseases are the result of complex and pathologically unbalanced multicellular interactions. It is, therefore, reasonable to assume that further molecular pathways and cellular components contribute to the anti-inflammatory effect of LD-RT. This review discusses data and models revealing aspects of the mechanisms underlying the anti-inflammation induced by low doses of X-irradiation and may serve as a basis for systematic analyses, necessary to optimize LD-RT in clinical practice.

Protection of Swiss albino mice against whole-body gamma irradiation by diltiazem

The aim of the present study was to evaluate the radioprotective effect of diltiazem (DTZ) on Swiss albino mice exposed to gamma radiation. In the present study, radioprotective efficacy of DTZ (a calcium channel blocker) was studied against radiation induced haematological and biochemical alterations. Swiss albino mice of 6-8 weeks old were administered diltiazem (100 mg kg(-1) by weight) intraperitoneally prior to whole body gamma-irradiation (7.5 Gy). Radiation exposure resulted in a significant decline in different bone marrow cells (pro- and normoblasts) and blood constituents (erythrocytes, leukocytes, differential leukocyte count, haematocrit, haemoglobin and erythrocyte sedimentation rate). Pro- and normoblasts, erythrocytes, leukocytes, haematocrit and haemoglobin values showed a significant (p<0.0051) decline until day 3, following a gradual recovery from day 7, but normal values were not recorded until 28 days post-exposure. In contrast, erythropoietin levels increased significantly and reached a maximum on day 3. In DTZ pre-treated irradiated animals, a significant increase in pro- and normoblasts, erythrocytes, leukocytes, differential leukocyte count, haematocrit and haemoglobin values, and a significant decrease in erythropoietin values, were observed compared with control. A significant elevation above normal in lipid peroxidation level was recorded in gamma irradiated mice, whereas this increase was considerably less in DTZ pre-treated animals. Similarly, pre-treatment of DTZ caused a significant increase in erythropoietin and glutathione levels in serum in comparison with irradiated animals. From our study it is clear that DTZ provides protection against radiation-induced haematological and biochemical alterations in Swiss albino mice.