Effects of Azadirachta indica seed kernel extracts on early erythrocytic schizogony of Plasmodium berghei and pro-inflammatory response in inbred mice.

BACKGROUND: Medicinal plant research may contribute to develop new pharmacological control tools for vector borne diseases, such as malaria. METHODS: The effects of methanol extracts (ME) obtained from seed kernel of ripe and unripe Azadirachta indica fruits were studied on erythrocytic proliferation of the rodent malaria parasite Plasmodium berghei strain ANKA and on mice pro-inflammatory response, as evaluated by measuring the matrix-metalloproteinase-9 (MMP-9) and tumour necrosis factor (TNF) plasma levels, in two mouse strains (C57BL/6 and BALB/c) which are considered as prototypical of Th1 and Th2 immune response, respectively. RESULTS: ME obtained from seed kernel of unripe Azadirachta indica fruits decreased by about 30% the proportion of erythrocytes infected with the malaria parasite in C57BL/6 mice in the 4 days suppressive test. In this treatment group, MMP-9 and TNF levels were notably higher than those measured in the same mouse strain treated with the anti-malarial drug artesunate, Azadirachta indica kernel extracts from ripe fruits or solvent. In BALB/c mice, treatment with kernel extracts did not influence parasitaemia. MMP-9 and TNF levels measured in this mouse strain were notably lower than those recorded in C57BL/6 mice and did not vary among treatment groups. CONCLUSIONS: The effects of the ME on the parasite-host interactions appeared to be mouse strain-dependent, but also related to the ripening stage of the neem fruits, as only the unripe fruit seed kernel extracts displayed appreciable bioactivity.

Glutathione transferase omega 1-1 (GSTO1-1) plays an anti-apoptotic role in cell resistance to cisplatin toxicity.

Several lines of evidence correlate the overexpression of glutathione S-transferase omega 1-1 (GSTO1-1) with the onset of drug resistance of cancer cells; however, no direct evidence is yet available. In order to investigate the mechanisms involved, stable transfection with GSTO1-1 complementary DNA was performed in HeLa cells, which spontaneously express very low levels of GSTO1-1. When transfected cells were seeded at low density, a sharp increase in GSTO1-1 expression was observed as compared with controls, along with an increased resistance against cisplatin cytotoxicity. When seeded at increasing densities, control untransfected cells also presented with an increase in GSTO1-1 expression, again accompanied by cisplatin resistance; the latter was significantly reduced after transfection with GSTO1-1 small interfering RNA. Cisplatin resistance of transfected cells was not accounted for by changes in the intracellular drug concentration nor in the amount of DNA cross-links or content of glutathione. Rather, transfected cells presented with a marked decrease of apoptosis as compared with controls, suggesting that GSTO1-1 overexpression may prevent cisplatin toxicity by interfering with the apoptotic process. Cisplatin treatment was in fact followed at early times (1-2 h) by activation of both Akt kinase and extracellular signal-regulated kinase (ERK)-1/2 in the transfected cells but not in controls. Conversely, in transfected cells, the strong activation of Jun N-terminal kinase (JNK)-1 induced by cisplatin at later times (10-20 h) was completely prevented. In conclusion, GSTO1-1 overexpression appears to be associated with activation of survival pathways (Akt and ERK1/2) and inhibition of apoptotic pathways (JNK1), as well as protection against cisplatin-induced apoptosis.

Nuclear translocation of glutathione transferase omega is a progression marker in Barrett's esophagus.

Barrett's esophagus (BE) represents a major risk factor for esophageal adenocarcinoma (AC). For this reason, patients with BE are subjected to a systematic endoscopic surveillance to detect initial evolution towards non-invasive neoplasia (NiN) and cancer, that eventually occurs only in a small fraction of BE patients. This study was aimed to investigate the possible role of glutathione-S-transferase-omega 1 (GSTO1), a recently discovered member of the glutathione-S-transferase family, as a progression marker in the Barrett's disease in order to improve the diagnosis of NiN in BE and to understand the mechanisms of the progression from BE to AC. We investigated the expression and subcellular localization of GSTO1 in biopsies from patients with BE and in human cancer cell lines subjected to heath shock treatment. A selective nuclear localisation of GSTO1 was found in 16/16 biopsies with low- or high-grade NiN, while it appeared in only 4/22 BE biopsies without signs of NiN (P<0.0001). Among biopsies of BE without NiN, diffuse (nuclear and cytoplasmic) staining was found in 5/22 cases, while selective cytoplasmic localisation was found in 13/22. The 6 cases with indefinite grade of NiN were equally divided between nuclear, cytoplasmic and diffuse staining (2 each, respectively). Experiments in vitro showed that in human HeLa cancer cells, GSTO1 translocates into the nucleus as a consequence of heath shock. These findings suggested that the nuclear translocation of glutathione-S-transferase-omega 1 could be involved in the stress response of human cells playing a role in the cancer progression of Barrett's esophagus. Its immunohistochemical detection could represent a useful tool in the grading of Barrett's disease.

Protective role of dehydroascorbate in rat liver ischemia-reperfusion injury.

BACKGROUND: Oxidative stress plays an important role in liver ischemia/reperfusion (I/R) injury. Thus, enhancing the liver antioxidant capacity could be a promising therapeutic strategy. Ascorbate (AA) is considered the perfect antioxidant, but its therapeutic efficacy is greatly limited by its slow achievement of high intracellular levels. This might be circumvented by administering dehydroascorbate (DHA), which presents a several-fold greater uptake than AA, and undergoes rapid intracellular reduction to AA. Thus, our aim was to assess the protective role of DHA in liver I/R injury. MATERIALS AND METHODS: Wistar rats (200-300 g bw) were pretreated iv with different doses of AA or DHA 20 min before liver ischemia, followed by 6 h reperfusion. Liver damage was assessed by biochemical and morphological indices. RESULTS: DHA pretreatment induced a rapid increase in liver ascorbate levels, significantly higher than findings for AA, without any significant reduction in glutathione levels. Liver damage during I/R in controls showed significant increases in serum transaminases and hepatic thiobarbituric acid reactive substances with alterations of liver morphology. DHA administration induced a clear, significant protection against I/R injury, whereas liver damage was only moderately prevented by AA. CONCLUSIONS: DHA might represent a simple, effective therapeutic option to prevent liver damage associated with ischemia/reperfusion.

Discordant effect of IFN-beta1a therapy on anti-IFN antibodies and thyroid disease development in patients with multiple sclerosis.

Interferon-beta1b (IFN-beta1b) therapy is associated with a relatively high risk of developing thyroid disease. IFN-beta1a is regarded as less immunogenic than IFN-beta1b because of its structural homology to natural IFN-beta. We assessed the effect of 1 year of IFN-beta1a treatment on thyroid function and autoimmunity in 14 multiple sclerosis (MS) patients. The results were compared with those obtained in a series of 31 MS patients treated with IFN-beta1b. The prevalence of positive binding antibody (BAb) titer and neutralizing (NAb) anti-IFN antibody titer in the two groups was also assessed. The BAb and NAb positivity rate in IFN-beta1a-treated patients was significantly lower than in the group submitted to IFN-beta1b therapy (7% vs. 84% and 0% vs. 30%, respectively). Although the incidence of thyroid dysfunction was slightly higher in IFN-beta1b-treated patients than in those undergoing IFN-beta1a treatment (33% vs. 23%, respectively), it did not reach statistical significance. Thyroid disease was unrelated to the presence of positive serum BAb or NAb titer in both the group undergoing IFN-beta1a therapy and in that treated with IFN-beta1b. In both groups, thyroid disease developed mostly in women (71%) against a background of preexisting thyroiditis and a diffuse hypoechoic ultrasound thyroid pattern (80%). IFN-beta1a treatment was associated with a significantly lower prevalence of both BAb and NAb-positive titers than was IFN-beta1b. Conversely, thyroid disease was similar and unrelated to the presence of positive anti-IFN-beta antibody titer. Therefore, routine thyroid assessment may be advised during IFN-beta1a treatment, especially in patients with preexisting thyroiditis.