Acute virulent infection with Plasmodium chabaudi does not impair the generation of a protective immune response

We have investigated whether a protective immune response occurred in mice infected with a virulent cloned strain of Plasmodium chabaudi. Animals inoculated intravenously with 10(7) parasitized erythrocytes (PE) showed an exponentially increasing parasitaemia and died by day 6 of the infection, presenting a pronounced anaemia. Smaller inocula produced a longer pre-patent period but did not change the lethal course of infection, since mice injected with 100 parasites died on day 12. When anaemia was compensated for by red blood cell (RBC) transfusion, infected mice recovered and thereafter exhibited a strong immunity, comparable to that of mice immunized by a drug-controlled infection. The immune response was P. chabaudi specific, as the mice were fully susceptible to a challenge by P. yoelii. Three transfusions of 5 x 10(9) RBC per mouse at 2-day intervals were necessary before all the animals were able to control the infection. Transfusion of a larger number of RBC resulted in a lower anaemia and a delay in reticulocytaemia but, paradoxically, the expression of the immune response was delayed. Three transfusions of 1.2 x 10(10) RBC enabled three out of eight mice to survive the infection, while six transfusions enabled all the mice to survive. The data suggest that parasitized immature RBC could play an important role in triggering the protective immune response.     

Bone loss in adult offspring induced by low-dose exposure to teratogens

Maternal malnutrition during pregnancy was shown by numerous studies to result in the birth of offspring exhibiting altered bone characteristics, which are indicative of bone loss. We hypothesized that not only maternal malnutrition but also some developmental toxicants (teratogens) given at a dose inducing neither structural anomalies nor growth retardation can detrimentally affect skeletal health in adult offspring. To check this hypothesis, pregnant mice were exposed to a single injection of 5-aza-2-deoxycytidine (5-AZA) (a teratogen capable of inducing phocomelia of the hind limbs) at a sub-threshold teratogenic dose. Micro-computed tomography scanning revealed that femora of 5-month-old male offspring exposed in uterus to 5-AZA had trabecular microarchitecture indicative of bone loss. Furthermore, exposure to 5-AZA increased the susceptibility of offspring to postnatal chronic mild stress, which has been shown to induce bone loss in mice. While exploring possible mechanisms underlying this phenomenon, we observed that the expression of some microRNAs, which have been demonstrated as regulators of key osteoblastogenic genes, was altered in hind limb buds of embryos exposed to 5-AZA. Furthermore, the expression of receptor activator of nuclear factor kappa B ligand (RANKL) in femoral stromal/osteoblastic cells of 5-month-old offspring of 5-AZA-treated females was found to be increased. Collectively, this study implies for the first time that single low-dose exposure to a teratogen can induce bone loss in adult offspring, possibly via alteration of embryonic microRNAs and RANKL expression.     

The anti-cancer agent SU4312 unexpectedly protects against MPP+-induced neurotoxicity via selective and direct inhibition of neuronal NOS

Background and Purpose

SU4312, a potent and selective inhibitor of VEGF receptor-2 (VEGFR-2), has been designed to treat cancer. Recent studies have suggested that SU4312 can also be useful in treating neurodegenerative disorders. In this study, we assessed neuroprotection by SU4312 against 1-methyl-4-phenylpyridinium ion (MPP⁺)-induced neurotoxicity and further explored the underlying mechanisms.

Experimental Approach

MPP⁺-treated neurons and 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-treated zebrafish were used to study neuroprotection by SU4312. NOS activity was assayed in vitro to examine direct interactions between SU4312 and NOS isoforms.

Key Results

SU4312 unexpectedly prevented MPP⁺-induced neuronal apoptosis in vitro and decreased MPTP-induced loss of dopaminergic neurons, reduced expression of mRNA for tyrosine hydroxylase and impaired swimming behaviour in zebrafish. In contrast, PTK787/ZK222584, a well-studied VEGFR-2 inhibitor, failed to prevent neurotoxicity, suggesting that the neuroprotective actions of SU4312 were independent of its anti-angiogenic action. Furthermore, SU4312 exhibited non-competitive inhibition of purified neuronal NOS (nNOS) with an IC₅₀ value of 19.0 μM but showed little or no effects on inducible and endothelial NOS. Molecular docking simulations suggested an interaction between SU4312 and the haem group within the active centre of nNOS.

Conclusions and Implication

SU4312 exhibited neuroprotection against MPP⁺ at least partly via selective and direct inhibition of nNOS. Because SU4312 could reach the brain in rats, our study also offered a support for further development of SU4312 to treat neurodegenerative disorders, particularly those associated with NO-mediated neurotoxicity.     

Maternal immunopotentiation affects caspase activation and NF-kappaB DNA-binding activity in embryos responding to an embryopathic stress

PROBLEM: Increased embryonic resistance to teratogenic stresses as a result of maternal immunopotentiation is associated with a decrease in the intensity of teratogen-induced apoptosis in target embryonic structures. These findings suggest that this effect of maternal immunopotentiation might be realized through modification of the expression of molecules regulating the teratogen-induced apoptotic process. To examine this possibility, we evaluated caspases 3, 8 and 9 activation as well as nuclear factor (NF)-kappaB DNA-binding activity in the embryos of immunopotentiated mice exposed to cyclophosphamide (CP). METHODS OF STUDY: The rate of resorptions and the proportion of malformed fetuses in CP-treated mice were recorded on day 19 of pregnancy. Activity of caspases was tested in cytoplasmic extracts collected from the embryonic brain 24 hr after CP treatment using appropriate fluorometric kits, whereas NF-kappaB DNA-binding activity was evaluated in nuclear extracts using the electrophoretic mobility shift assay. RESULTS: As in our previous studies, immunopotentiated CP-treated females exhibited a lower rate of resorptions or fetuses with open eyes than their non-immunopotentiated counterparts. In parallel, we observed that maternal immunopotentiation normalized the CP-induced activation of the tested caspases as well as the CP-induced suppression of NF-kappaB DNA-binding activity. CONCLUSIONS: As caspases act as inducers of apoptosis, and NF-kappaB acts in CP-treated embryos as an apoptosis suppressor, the above results suggest that maternal immunopotentiation might affect embryonic sensitivity to embryopathic stresses via NF-kappaB- and caspases-associated pathways.     

用超临界流体色谱法测定怀牛膝及其制剂中齐墩果酸的含量

采用超临界流体色谱法(SFC)分别测定了不同产地的怀牛膝药材及三种含怀牛膝的制剂中齐墩果酸的含量。方法简单、快速。不需经特殊的纯化处理。各产地药材齐墩果酸含量波动较小(1.75～2.19%,x±SD=1.94±0.17%),可以作为药材与制剂质量评价的指标,药材的加样回收率为97.42%(n=18,RSD=2.80%);制剂天麻丸的加样回收率为94.82%(n=9,RSD=2.51%)。     

In renal transplantation blood cyclosporine levels soon after surgery act as a major determinant of rejection: insights from the MY.S.S. trial

BACKGROUND: Target organs express antigens recognized directly by antigen-specific T cells, and their recognition is crucial to precipitate rejection. Then, the earliest T-cell activation is inhibited by cyclosporine A (CsA), the lowest would be the risk of rejection. Here, we aimed to assess this possibility in a large cohort of de novo kidney transplant recipients participating in an ongoing clinical trial, the Mycophenolate Steroid-Sparing (MY.S.S.) Trial. METHODS: Three-hundred-thirty-four patients entered the prospective, multicenter MY.S.S. trial. The main aim of the study was to assess the predictive value of serial evaluation of blood CsA trough concentration (C0) and 2-hour postdose drug (C2) levels alone or in combination, and to identify which is the critical posttransplant measurement to target CsA therapy in order to minimize the risk of acute rejection. A very large number of CsA trough (N= 2236) and C2 (N= 2128) measurements during the first 6 months postsurgery were available for analysis. Patients with delayed graft function were excluded. RESULTS: CsA trough levels measured at day 2 posttransplant were the strongest predictor of acute graft rejection over 6-month follow-up. Levels within 300 to 440 ng/mL were associated with the lowest risk of rejection, while for levels lower than 300 ng/mL, the risk of acute rejection was more than doubled. Higher levels failed to provide any further protection from graft rejection. CsA trough values predicted allograft rejection with an accuracy of 74%, while C2 levels considered alone had no predictive values at all. CONCLUSION: Findings that among serial daily measurements posttransplant those taken as early as at day 2 have by far the highest capacity to predict rejection episodes, underline the need of targeting CsA therapy very early posttransplant with the goal to modulate early enough T-cell activation at the interface between the recipient's blood and the graft where alloimmune response actually initiates.     

Diabetes teratogenicity is accompanied by alterations in macrophages and T cell subpopulations in the uterus and lymphoid organs

Insulin-dependent diabetes mellitus is a well-known teratogen, which might cause growth retardation, malformations and fetal death. We have previously shown, that potentiation of the maternal immune system (immunopotentiation) might protect the embryo from diabetes teratogenicity. Therefore, in the present study we further inquired whether diabetes teratogenicity might be associated with alterations in the level of immune effector cells in systemic and local lymphoid organs as well as in the uterus throughout pregnancy and whether the protection exerted by maternal immunopotentiation might be realized through its effect on those cells. Streptozotocin-induced diabetes in ICR mice was found to reduce pregnancy rate and fetal weight while increasing the resorption rate and the percentage of litters with malformed fetuses. These teratogenic effects were accompanied by a decreased percentage of cells expressing Mac-1, Thy-1.2, CD4 or CD8 in the spleen and inguinal as well as paraaortic lymph nodes, except for Mac-1 expression by splenocytes, which increased significantly in the beginning of pregnancy and decreased later. A different pattern was observed in the uterus, when the percentage of cells expressing these markers tended to increase in the beginning of pregnancy and decrease later. Intrauterine immunopotentiation with rat splenocytes was found to improve the reproductive performance of diabetic animals. This protective effect was accompanied by a general normalization of the level of the various cell surface markers, when in most cases their expression returned to that found in nonimmunopotentiated mice. Our results suggest that the protection exerted by maternal immunopotentiation on the embryo against diabetes teratogenicity might be mediated via its effect on the level of immune effector cells localized to uterus and lymphoid organs, which was found to be altered in diabetic mice.