Capsaicin attenuates immunosuppression induced by chronic stress in BALB/C mice

Although acute stress generally exerts positive effects on the immune system, chronic stress typically causes immunosuppression via the hypothalamic-pituitary-adrenal (HPA) axis. In this study, the effects of capsaicin (1.28 mg/kg intraperitoneally [i.p.] for 7 days) on immune parameters were evaluated under conditions of chronic stress. Capsaicin treatment significantly increased the immune response as evaluated by the delayed-type hypersensitivity (DTH) reaction to dinitrofluorobenzene (DNFB) and splenocyte proliferation assays- It also is able to rescue the splenocytes of the apoptosis induced by stress. The capsaicin treatment increased the production of Th1 cytokines and decreased the production of Th2 cytokines and TGF-β1 in the plasma and culture supernatants of immunosuppressed mice, which is associated with the modulation of Th2 induced by stress cells. Moreover, the production of corticosterone significantly decreased in capsaicin-treated animals as compared to control groups. The capsaicin treatment further attenuated the immunosuppression induced by the corticosterone treatment (40 mg/kg i.p. for 7 days), albeit less potently, as exhibited in the DTH response. Intriguingly, the capsaicin treatment decreased the induction of IL-10, IL-4, and TGF-β1 through high doses of corticosterone, indicating direct cellular immunomodulation. These results show, that capsaicin is able to modulate chronic stress-induced immunosuppression, mediating corticosterone released inhibition, but also, that capsaicin significantly modulates the pharmacological action of corticosterone in vivo.

In vitro induction of apoptosis in U937 cells by perillyl alcohol with sensitization by pentoxifylline: increased BCL-2 and BAX protein expression

BACKGROUND

Chemotherapy is effective against a wide variety of tumor cells, although its use is limited by side effects. In vitro experiments and phase I and II trials have shown that phytochemicals such as perillyl alcohol (P-OH) have antitumor effects. Pentoxifylline (PTX), a synthetic methylxanthine used mainly to treat pathologies associated with hematological diseases, sensitizes tumor cells to chemotherapy. The aim of this study was to determine whether PTX amplifies the antitumor effects of P-OH in U937 human myelomonocytic leukemia cells.

METHODS

Apoptosis was measured by the loss of mitochondrial membrane potential determined by flow cytometry using dihexyloxacarbocyanine iodide (DiOC6) and propidium iodide. Bcl-2 and Bax protein expression was also assessed by Western blot analysis.

RESULTS

P-OH and PTX induced loss of the mitochondrial membrane potential in U937 cells in vitro. Culturing the cells in the presence of both compounds caused a significant increase (p < 0.001) in apoptosis and expression of anti-apoptotic Bcl-2 and pro-apoptotic Bax proteins. However, despite their coexistence, Bax expression prevailed in our experiments. These data suggest that the effects of PTX might be attributable to changes in the mitochondrial membrane potential.

CONCLUSION

PTX sensitizes tumor cells to the anti-neoplastic action of P-OH. These observations may have clinical relevance in the treatment of cancer patients.

Retinopatía del prematuro y estrés oxidativo

INTRODUCTION

There is some evidence that retinopathy of prematurity is due to excessive oxidative stress on the developing retina caused by high free radical production or reduced ability to eliminate these radicals.

OBJECTIVE

To determine the relationship between high levels of oxidative stress and retinopathy of prematurity.

MATERIAL AND METHODS

A prospective cohort study was designed. Fifty premature infants of less than 33 weeks' gestational age were included. Serum lipoperoxide levels were determined as a measure of oxidative stress. Samples were taken once a week for 1 month, starting from the first week of life. The results of all four samples were compared between infants who developed any degree of retinopathy of prematurity and those without it. Ophthalmological examinations were performed after the fourth week of life.

RESULTS

The incidence of retinopathy of prematurity was 22 % (11/50). The mean values of all the samples showed a significant difference between infants who developed retinopathy of prematurity (5.44 +/- 1.30 nmol/ml) and those who did not (2.94 +/- 0.89 nmol/ml, p = 0.0001). The relative risk of developing retinopathy of prematurity with high serum lipoperoxide levels was 5.15, 5.63, 4.15 and 12.70 for each of the weekly samples.

CONCLUSIONS

There is an association between high serum lipoperoxide levels, as a measure of oxidative stress, and the incidence of retinopathy of prematurity.

In vivo modification of adriamycin-induced apoptosis in L-5178Y lymphoma cell-bearing mice by (+)-alpha-tocopherol and superoxide dismutase

Apoptosis was followed in L5178Y lymphoma cell-bearing mice at different times after intraperitoneal injections of adriamycin (ADM). Apoptosis was determined morphologically and confirmed by DNA laddering on electrophoresis. Apoptosis was observed 36h after injection of 5mg/kg ADM (apoptotic cell index 64.2+/-5.6 vs. 1.5+/-2.1 from the untreated group) and confirmed by DNA electrophoresis. However, when the animals were pretreated with (+)-alpha-tocopherol acid succinate or superoxide dismutase before ADM administration apoptotic index significantly diminished (P<0.05) and the DNA electrophoresis did not show fragmentations. We conclude that in ADM-treated mice, tumour cell death occurs in two ways: first by necrosis, then later by apoptosis. These observations are likely to be associated with or caused by the generation of reactive oxygen species.

Enhanced functional capacity of the peritoneal macrophages as antigen presenting cells after aclacinomycin treatment in mice

Aclacinomycin (ACM) is an oncostatic of the anthracycline family, largely used in patients and experimentally in mice. ACM has been reported to enhance phagocytosis, secretion of free oxygen radicals and of interleukin 1. Its injection is also followed by an increase of the cytotoxic and cytostatic activity of murine peritoneal macrophages. In the present work we investigated whether ACM modifies the antigen-presenting cell capacity of murine peritoneal macrophages. Purified T lymphocytes were cultured with peritoneal macrophages from either normal or ACM treated mice (4 mg/kg day -4) which were previously incubated with phytohemagglutinin. The T cell proliferative response was greater in cultures with normal macrophages, indicating that macrophages from ACM-treated mice had a better antigen presenting activity than normal untreated macrophages.