Effect of low-dose irradiation upon T cell subsets involved in the response of primed A/J mice to SaI cells

Prostaglandin E1 administration post liver transplantation and renal outcomes: A retrospective single center experience

BACKGROUND

Prostaglandin E1 (PGE1), or alprostadil, is a potent vasodilator that improves hepatic blood flow and reduces ischemia-reperfusion injury post-liver transplantation (LT). However, the benefits of PGE1 on renal function after LT have not yet been well described.

AIM

To assess the impact of PGE1 administration on renal function in patients who underwent liver or liver-kidney transplant.

METHODS

This retrospective study included all patients who underwent liver or liver-kidney transplant at our institution from January, 2011 to December, 2021. Patients were classified based on whether they received PGE1. PGE1 was administered post-LT to those with transaminases > 1000 U/L in the immediate postoperative period. Demographics, post-LT treatments and/or complications, renal function, and survival were analyzed. Multivariable logistic regression analysis was performed, and a two-tailed P value < 0.05 was considered statistically significant.

RESULTS

A total of 145 patients underwent LT, with 44 (30%) receiving PGE1. Baseline patient characteristics were comparable, except the PGE1 group had significantly higher aspartate aminotransferase (AST) (1961.9 U/L ± 1862.3 U/L vs 878 U/L ± 741.4 U/L, P = 0.000), alanine aminotransferase (1070.6 U/L ± 895 U/L vs 547.7 U/L ± 410 U/L, P = 0.000), international normalized ratio on post-LT day 1 (2 ± 0.74 vs 1.8 ± 0.4, P = 0.03), a longer intensive care unit stay (8.1 days ± 11.8 days vs 3.8 days ± 4.6 days, P = 0.003), more vasopressor use (55.53 hours ± 111 hours vs 16.33 hours ± 26.3 hours, P = 0.002), and higher immediate postoperative complications (18.6% vs 4.9%, P = 0.04). The PGE1 group also had a significantly higher 90-day readmission rate (29.6% vs 13.1%, P = 0.02) and lower 1-year liver graft survival (87.5% vs 98.9%, P = 0.005). However, 30-day readmission (31.6% vs 27.4%, P = 0.64), LT complications (hepatic artery thrombosis, biliary complications, rejection of liver graft, cardiomyopathy), 1-year patient survival (96.9% vs 97.8%, P = 0.77), overall liver graft survival, and overall patient survival were similar between the two groups (95.4% vs 93.9%, P = 0.74 and 88.4% vs 86.9%, P = 0.81 respectively). Although the PGE1 group had a significantly lower glomerular filtration rate (eGFR) on post-LT day 7 (46.3 mL/minute ± 26.7 mL/minute vs 62.5 mL/minute ± 34 mL/minute, P = 0.009), the eventual need for renal replacement therapy (13.6% vs 5.9%, P = 0.09), the number of dialysis sessions (0.91 vs 0.27, P = 0.13), and eGFR at 1-month (37.2 mL/minute ± 35.9 mL/minute vs 42 mL/minute ± 36.9 mL/minute, P = 0.49), 6-months (54.8 mL/minute ± 21.6 mL/minute vs 62 mL/minute ± 21.4 mL/minute, P = 0.09), and 12-months (63.7 mL/minute ± 20.7 mL/minute vs 62.8 mL/minute ± 20.3 mL/minute, P = 0.85) post-LT were similar to those in the non-PGE1 group.

CONCLUSION

In patients who received PGE1 for ischemia-reperfusion injury, despite immediate acute renal injury post-LT, the renal function at 1-month, 6-months, and 12-months post-LT was similar compared to those without ischemia-reperfusion injury. Prospective clinical trials are needed to further elucidate the benefits of PGE1 use in renal function.

Exploring low-dose radiotherapy to overcome radio-immunotherapy resistance

Immune checkpoint inhibitors (ICIs) have revolutionized the current treatment landscape for cancer, yet the response rates of ICIs remain unmet. Synergistic with immunotherapy, low-dose radiotherapy (LDRT) has been demonstrated to activate anti-tumor immunity - a transition from traditional radiation therapy geared toward local radical treatment to a type of immunological adjuvant. As such, studies utilizing LDRT to enhance the efficacy of immunotherapy have been increasing preclinically and clinically. This paper reviews the recent strategies of using LDRT to overcome the resistance of ICIs, as well as providing potential opportunities in cancer treatment. Despite the potential of LDRT in immunotherapy is recognized, the mechanisms behind this form of treatment remain largely elusive. Thus, we reviewed history, mechanisms and challenges associated with this form of treatment, as well as different modes of its application, to provide relatively accurate practice standards for LDRT as a sensitizing treatment when combined with immunotherapy or radio-immunotherapy.

Effects of Radon From Hot Springs on Lymphocyte Subsets in Peripheral Blood

Objective:

To analyze changes in immune functions by detecting lymphocyte subsets in the peripheral blood of residents in the vicinity of radon from hot springs.

Methods:

Two groups were randomly selected; 61 residents in the vicinity of the hot springs were assigned to the radon group, and 51 residents with a similar lifestyle and habits but no contact with hot springs were assigned to the control group. The percentages of lymphocyte subsets (CD3⁺, CD4⁺CD8⁻, CD4⁻CD8⁺, CD4⁺/CD8⁺, and TCR/CD3) in the 2 groups were evaluated on a FACS Aria flow cytometer. The absolute values of lymphocytes (LYMPH#) and percentages of lymphocytes (LYMPH%) were measured by an automatic blood analyzer.

Results:

In the radon group, the numbers of CD3⁺ (Z = −0.140, P > .05) and CD4⁺CD8⁻ (Z = −0.964, P > .05) T cells were higher, as compared with the controls, but this difference was not significant. In addition, the number of CD4⁻CD8⁺ (t = −2.141, P < .05) T cells was significantly lower in the radon group. Furthermore, the average ratios of CD4⁺/CD8⁺ (t = −2.201, P < .05) and TCR/CD3 (t = 2.047, P < .05) cells were significantly higher in the radon group than in the controls. Compared with the control group, the LYMPH# (t = −0.485, P > .05) and LYMPH% (Z = −0.835, P > .05) showed no significant change.

Conclusion:

Radon-rich hot springs could alter the proportions of lymphocyte subsets and possibly affect immunologic functions.

Antioxidant Supplementation: A Linchpin in Radiation-Induced Enteritis

Radiation enteritis is one of the most feared complications of abdominal and pelvic regions. Thus, radiation to abdominal or pelvic malignancies unavoidably injures the intestine. Because of rapid cell turnover, the intestine is highly sensitive to radiation injury, which is the limiting factor in the permissible dosage of irradiation. Bowel injuries such as fistulas, strictures, and chronic malabsorption are potentially life-threatening complications and have an impact on patient quality of life. The incidence of radiation enteritis is increasing because of the current trend of combined chemotherapy and radiation. The consequences of radiation damage to the intestine may result in considerable morbidity and even mortality. The observed effects of ionizing radiation are mediated mainly by oxygen-free radicals that are generated by its action on water and are involved in several steps of signal transduction cascade, leading to apoptosis. The oxyradicals also induce DNA strand breaks and protein oxidation. An important line of defense against free radical damage is the presence of antioxidants. Therefore, administration of antioxidants may ameliorate the radiation-induced damage to the intestine.

Effects of low-dose-gamma rays on the immune system of different animal models of disease

We reviewed the beneficial or harmful effects of low-dose ionizing radiation on several diseases based on a search of the literature. The attenuation of autoimmune manifestations in animal disease models irradiated with low-dose γ-rays was previously reported by several research groups, whereas the exacerbation of allergic manifestations was described by others. Based on a detailed examination of the literature, we divided animal disease models into two groups: one group consisting of collagen-induced arthritis (CIA), experimental encephalomyelitis (EAE), and systemic lupus erythematosus, the pathologies of which were attenuated by low-dose irradiation, and another group consisting of atopic dermatitis, asthma, and Hashimoto's thyroiditis, the pathologies of which were exacerbated by low-dose irradiation. The same biological indicators, such as cytokine levels and T-cell subpopulations, were examined in these studies. Low-dose irradiation reduced inter-feron (IFN)-gamma (γ) and interleukin (IL)-6 levels and increased IL-5 levels and the percentage of CD4(+)CD25(+)Foxp3(+)Treg cells in almost all immunological disease cases examined. Variations in these biological indicators were attributed to the attenuation or exacerbation of the disease's manifestation. We concluded that autoimmune diseases caused by autoantibodies were attenuated by low-dose irradiation, whereas diseases caused by antibodies against external antigens, such as atopic dermatitis, were exacerbated.

Analysis of blood lymphocyte subsets in children living around Chernobyl exposed long-term to low doses of cesium-137 and various doses of iodine-131

Epidemiological studies have found that children living around Chernobyl have rates of respiratory tract illness that are higher than those seen in the area before the Chernobyl accident. The present study investigates the possible effects of radiation exposure on the composition of peripheral blood lymphocyte subsets in children living around Chernobyl. Two hundred nineteen healthy children and children suffering from recurrent respiratory diseases aged 6-14 years who received both low doses of radiation to the whole body from (137)Cs and various doses of radiation to the thyroid from (131)I as fallout from the accident were assessed 5 (1991) and 8-10 years (1994-1996) after the accident. A total of 148 healthy children and children suffering from recurrent respiratory diseases living in noncontaminated areas were also evaluated as controls. Children with recurrent respiratory diseases who lived around Chernobyl had a significantly lower percentage of T cells and a higher percentage of NK cells compared to control children with recurrent respiratory diseases during the study period. In contrast to the findings in 1991, a significant decrease in the percentage of helper-inducer cells was observed in children with recurrent respiratory diseases in 1994-1996. In contrast to 1991, there is a positive correlation between the percentage of helper-inducer cells, the helper-inducer/cytotoxic-suppressor cell ratio, and the dose of radiation to the thyroid of healthy children from (131)I in 1994-1996. There was a positive correlation between the dose of radiation to the thyroid from (131)I and the percentage of helper-inducer cells in children with recurrent respiratory diseases 5 years (1991) after the accident. Further, the dose of radiation to the thyroid from (131)I correlated negatively with the percentage of T and B cells and positively with the percentage of NK cells in children with recurrent respiratory diseases 8-10 years (1994-1996) after the accident. These results raise the possibility that long-term exposure to low doses of (137)Cs may have altered the composition of the T-cell subsets and NK cells in children with recurrent respiratory diseases. The differences in the composition of the peripheral blood lymphocyte subsets between healthy children and those with recurrent respiratory diseases may be attributed to long-term low-dose exposure of the whole body to radiation from (137)Cs and exposure of the thyroid to radiation from (131)I subsequent to the Chernobyl accident.

Effect of combination treatment of 15 cGy total body irradiation and OK-432 on spontaneous lung metastasis and mitogenic response of splenocytes in mice

We investigated whether the combination treatment of 15 cGy total body irradiation (TBI) and a streptococcal preparation, OK-432, synergistically suppresses spontaneous lung metastasis and augments phytohemagglutinin (PHA) and concanavalin A (Con A) responses of splenocytes in WHT/Ht mice. TBI with 15 cGy was carried out 20 days after subcutaneous injection of squamous cell carcinoma cells into a hind leg. Lung colony number was counted 40 days after tumor injection. For PHA and Con A responses, mice were killed 4 hr after 15 cGy TBI. The combination treatment of 15 cGy TBI and OK-432 was most effective when OK-432 was administered 2 days before 15 cGy TBI. The combination treatment decreased the lung colony number to 29.9% of the control number. OK-432 slightly increased the PHA and Con A responses, and 15 cGy TBI did not increase them. However, when these two were combined, the PHA and Con A responses were significantly increased to 393% and 278% of the control levels, respectively. It was suggested that TBI and OK-432 acted synergistically in suppressing the lung metastasis and mitogenic response of splenocytes.

Analgesia induced by repeated exposure to low dose x-rays in mice, and involvement of the accessory olfactory system in modulation of the radiation effects

The effects of low-dose x-rays on mouse nociceptive behavior were examined using a formalin injected test that rated the amount of time the animals spent licking the injected hind paw. Male ICR White Swiss mice showed a marked suppression of licking behavior after repeated low-dose x-irradiation (5 cGy/day, 6 consecutive days). The most profound effect was observed on the day 30 after irradiation. The decline of licking behavior, however, was not observed at all following olfactory bulbectomy or vomeronasal tract cut. The analgesic effects could be observed in writhing animals administered acetic acid intraperitoneally. Moreover, analgesia was totally blocked by the administration of N-nitro-L-arginine, a nitric oxide synthase inhibitor, to accessory olfactory bulbs prior to the exposure. The present results indicate that the olfactory system plays an important role in modulation of radiation-induced analgesia, and a possible involvement of nitric oxide in the formation of recognition memory subjected to repeated x-rays. Relatively higher doses (5 cGy x 9 days, 5 cGy x 12 days), however, did not induce such effects, namely, the decline of nociceptive response was limited to the animals irradiated with the smaller dose.

Prostacyclin production in cultured endothelial cells is highly sensitive to low doses of ionizing radiation

In an attempt to detect if low doses of ionizing radiation affect the physiological function of blood vessels, the effect of prostacyclin production was examined using cultured endothelial cells. Irradiation with 5 cGy suppressed the production to 53% of the levels in unirradiated control cells. The PGI2 production decreased with an increase in the dose, showing a maximal decrease at 100 cGy without further decrease at 200 cGy. The suppressive effect lasted for 15 min after irradiation and disappeared later. Preincubation with alpha-tocopherol abrogated the suppressive effect completely, although preincubation with ascorbic acid showed little effect. These results suggest that low dose irradiation inhibits the prostacyclin production by changing the cellular membranes transiently.

Suppressive effect of low dose total body irradiation on lung metastasis: dose dependency and effective period

The dose dependency and effective period of suppressive effects by low dose total body irradiation (TBI) in both artificial and spontaneous lung metastasis were investigated using murine squamous cell carcinoma. In the artificial lung metastasis of the tumour cells injected through a tail vein, the TBI of 0.15-0.20 Gy resulted in significant net suppression of lung colony formation. With this dose range, the effective period lasted for 12 h ranging from 9 h before to 3 h after the tumour cell injection. Similar suppressive effect was also observed in the spontaneous lung metastasis. These data suggest that careful assessment of effective dose and duration of low dose TBI on human metastasis could provide a new therapy to suppress clinical metastasis.

T-lymphocyte subsets in occupationally exposed persons

The percentage of CD2+, CD4+, CD8+ and HNK-1+ cells in peripheral blood was investigated in persons occupationally exposed to very low doses of ionizing radiation. Investigations were carried out by monoclonal antibodies and flow cytometry. While significant effects of age and smoking habits on the relative number of CD8 cells and CD4/CD8 ratios could be established, no influence of the very low radiation exposure on the profile of lymphocytic T cells in blood was found, except a very slight effect on the relative number of CD2+ cells.

The effect of fetal irradiation on the growth of postnatally xenotransplanted tumour cells

Exposure of the mouse fetus (NMRI-strain) to 1.0 Gy X-irradiation has a marked effect on postnatally xenotransplanted glioma cells. In comparison to non-irradiated animals, irradiation on gestation day 14 resulted in: (a) a significantly higher rate of animals which failed to develop visible tumours growing from the inoculum; (b) a significant inhibition of the growth rate of solid gliomas; (c) a pronounced granulocytic and mast cell infiltration, and tissue necrosis, in the invading gliomas. The results suggest that irradiation in prenatal life exerts an amplifying effect on the antitumour response in postnatal life.

Altruistic cell suicide in relation to radiation hormesis

The high radiosensitivity to killing of undifferentiated primordial cells (Bergonié and Tribondeau 1906) can be described as a manifestation of the suicide of injured cells for the benefit of an organism as a whole if their suicide stimulates proliferation of healthy cells to replace them, resulting in complete elimination of injury. This process is called cell-replacement repair, to distinguish it from DNA repair which is rarely complete. 'Cell suicide', 'programmed death' and 'apoptosis' are terms used for the same type of active cell death. Cell suicide is not always altruistic. Altruistic suicide in Drosophila, mice, humans, plants, and E. coli is reviewed in this paper to illustrate its widely different facets. The hypothesis that in animals, radiation hormesis results from altruistic cell suicide is proposed. This hypothesis can explain the hormetic effect of low doses of radiation on the immune system in mice. In contrast, in plants, radiation hormesis seems to be mainly due to non-altruistic cell death. HORMESIS--'the stimulating effect of small doses of substances which in larger doses are inhibitory' (British Medical Dictionary, Caxton Publ. Co., 1961).