Deviation of pancreas-infiltrating cells to Th2 by interleukin-12 antagonist administration inhibits autoimmune diabetes

Nonobese diabetic (NOD) mice develop spontaneous insulin-dependent diabetes mellitus (IDDM), and the pancreas-infiltrating T cells invariably show a Th1 phenotype. We demonstrated here that the interleukin (IL)-12 antagonist (p40)₂ can deviate the default Th1 development of naive T cell receptor (TCR)-transgenic CD4⁺ cells to the Th2 pathway in vitro. Although (p40)₂ does not modify the cytokine profile of polarized Th1 cells, it prevents further recruitment of CD4⁺ cells into the Th1 subset. To study the involvement of Th1 and Th2 cells in the initiation and progression of IDDM, we targeted endogenous IL-12 by administration of (p40)₂ in NOD mice. (p40)₂ administration to NOD mice inhibits interferon-γ but not IL-10 production in response to lipopolysaccharide (LPS) or to the putative autoantigen IA-2. Serum immunoglobulin isotypes determined after (p40)₂ treatment indicate an increase in Th2 and a decrease in Th1 helper activity. Administration of (p40)₂ from 3 weeks of age onwards, before the onset of insulitis, results in the deviation of pancreas-infiltrating CD4⁺ but not CD8⁺ cells to the Th2 phenotype as well as in the reduction of spontaneous and cyclophosphamide-accelerated IDDM. After treating NOD mice with (p40)₂ from 9 weeks of age, when insulitis is well established, few Th2 and a reduced percentage of Th1 cells are found in the pancreas. This is associated with a slightly decreased incidence of spontaneous IDDM, but no protection from cyclophosphamide-accelerated IDDM. In conclusion, deviation of pancreas-infiltrating CD4⁺ cells to Th2 is associated with protection from IDDM. However, targeting IL-12 after the onset of insulitis, when the pancreas contains polarized Th1 cells, is not sufficient to induce an effective immune deviation able to significantly modify the course of disease.     

Differential migration behavior and chemokine production by myeloid and plasmacytoid dendritic cells

The existence of dendritic cell (DC) subsets is firmly established, but their trafficking properties are still largely unknown. We have indicated that myeloid dendritic cells (M-DCs) and plasmacytoid dendritic cells (P-DCs) isolated from human blood differ widely in the capacity to migrate to chemotactic stimuli. The pattern of chemokine receptors expressed ex vivo by both subsets is similar, but P-DCs display, compared with M-DCs, higher levels of CC chemokine receptor (CCR)5, CCR7, and CXCR3. Intriguingly, most chemokine receptors of P-DCs, in particular those specific for inflammatory chemokines and classical chemotactic agonists, are not functional in circulating cells. Following maturation induced by cluster designation (CD)40 ligation, the receptors for inflammatory chemokines are downregulated and CCR7 on P-DCs becomes coupled to migration. The drastically impaired capacity of blood P-DCs to migrate in response to inflammatory chemotactic signals contrasts with the response to lymph node-homing chemokines, indicating a propensity to migrate to secondary lymphoid organs rather than to sites of inflammation. The distinct migration behavior of DC subsets is accompanied by a different profile of chemokine production. In contrast to the high production by M-DCs, the homeostatic CC chemokine ligand (CCL)17/ thymus- and activation-regulated chemokine (TARC) is not produced by PDCs in response to any stimulus tested and their production of CCL22/MDC is minimal, if any, compared with M-DCs. Thus, stimulated M-DCs, but not P-DCs, are able to produce high levels of chemokines recruiting T-helper 2 cells (Th2) and T-regulatory cells. Conversely, the proinflammatory chemokine CCL3/macrophage inflammatory protein (MIP)-1 is predominantly produced by P-DCs. Therefore, P-DCs appear to produce preferentially proinflammatory chemokines, but to respond selectively to homeostatic ones, whereas the reverse is true for M-DCs, highlighting not only the different migratory properties of these DC subsets, but also their capacity to recruit different cell types at inflammation sites.     

The involvement of IL-12 in murine experimentally induced autoimmune thyroid disease.

Experimental autoimmune thyroid disease (EAT) can be induced experimentally in mice following immunization with mouse thyroglobulin (mTg) and the adjuvants lipopolysaccharide (LPS) or complete Freund's adjuvant (CFA). EAT can also be transferred to naive recipients by CD4+ T cells from mTg-primed mice. Here we demonstrate a role for IL-12 in the development of EAT by the ability of neutralizing antibody to IL-12 to reduce disease severity and by the lack of significant levels of thyroid infiltration in IL-12p40-deficient mice following immunization with mTg and CFA. A single injection of 300 ng IL-12 at the time of initial immunization with mTg and LPS was able to increase the degree of thyroid infiltration. These data are all consistent with EAT being a Th1-mediated disease. Conversely, however, administration of IL-12 over a prolonged period markedly inhibited the induction of EAT by mTg and CFA and, if given to recipients, inhibited the transfer of EAT by mTg-primed lymph node cells. The development of an autoantibody response to mTg was also inhibited when IL-12 was administered throughout the experimental period, suggesting that sustained exposure to IL-12 can be immunosuppressive.     

The anatomical scaffold underlying the functional centrality of known cortical hubs

Cortical hubs play a fundamental role in the functional architecture of brain connectivity at rest. However, the anatomical scaffold underlying their centrality is still under debate. Certainly, the brain function and anatomy are significantly entwined through synaptogenesis and pruning mechanisms that continuously reshape structural and functional connections. Thus, if hubs are expected to exhibit a large number of direct anatomical connections with the rest of the brain, such a dense wiring is extremely inefficient in energetic terms. In this work, we investigate these aspects on fMRI and DTI data from a set of know resting‐state networks, starting from the hypothesis that to promote integration, functional, and anatomical connections link different areas at different scales or hierarchies. Thus, we focused on the role of functional hubs in this hierarchical organization of functional and anatomical architectures. We found that these regions, from a structural point of view, are first linked to each other and successively to the rest of the brain. Thus, functionally central nodes seem to show few strong anatomical connections. These findings suggest an efficient strategy of the investigated cortical hubs in exploiting few direct anatomical connections to link functional hubs among each other that eventually reach the rest of the considered nodes through local indirect tracts. Hum Brain Mapp 38:5141–5160, 2017. © 2017 Wiley Periodicals, Inc.     

Transanal total mesorectal excision: Myths and reality

Transanal total mesorectal excision (TaTME) is a new and promising approach for the treatment of rectal cancer. Whilst the experience is still limited, there are growing evidences that this approach might overcome the limits of standard low anterior resection. TaTME might help to decrease the conversion rate especially in difficult patients, and to improve the pathological results, while preserving the urogenital function. Evaluation of data from large registries and randomized studies should help to draw firmer conclusions. Beyond these technical considerations, the next challenge seems to be clearly the safe introduction of this approach, motivating the development of dedicated courses.     

Influence of Pluronic® F68 on Ceftazidime Biological Activity in Parenteral Solutions

β-Lactam antimicrobials are known to have a low concentration/therapeutic response. However, extending the period in which β-lactam are free in the plasma does directly influence therapeutic outcomes. The objective of this study was to evaluate the influence of Pluronic® F68 on the antimicrobial activity of ceftazidime when admixed with aminophylline in parenteral solutions by the evaluation of its minimal inhibitory concentration (MIC) within 24 h. Ceftazidime, aminophylline, and Pluronics® F68 were evaluated using the MIC method against Escherichia coli and Pseudomonas aeruginosa, with these compounds individually and associated in the same parenteral solutions. When Pluronics® F68 was admixtured with ceftazidime alone or with ceftazidime and aminophylline, it was possible to observe lower MIC values not only at 24 h but also at 0 h for both microorganisms. This indicates that Pluronics® F68 may be able to enhance ceftazidime antimicrobial activity in the presence or absence of aminophylline. This fact suggests that Pluronics® F68 can be applied to allow the administration of ceftazidime under continuous infusion in parenteral solutions, beneficiating hospital pharmacotherapy. It may also be possible to reduce ceftazidime doses in formulations achieving the same therapeutic results.     

Interleukin-10 and regeneration in an end-to-side nerve repair model of the rat

End-to-side (ETS) neurorrhaphy is an option in peripheral nerve surgery. The aim of this study was to investigate whether the application of the anti-inflammatory cytokine interleukin-10 (IL-10) reduces scarring and thus enhances nerve regeneration in an ETS peroneal/tibial nerve lesion model of the rat. Twenty rats with a peroneal to tibial ETS neurorrhaphy were divided into two groups: (1) control group and (2) IL-10 group with intrafascicular application of 0.125 μg/100 μl IL-10. Survival time was 8 weeks. Nerve conduction velocities (NCVs) and motor function were analyzed and histomorphological evaluation with measurement of intraneural collagen level, axon count, total nerve area, and myelination index followed. Evaluation of motor function and nerve conduction did not show any statistical differences. Histological analyses revealed thicker myelin sheaths and higher myelination index in the IL-10 group (p < 0.001). Axon count showed no difference. The IL-10 group revealed lower collagen levels (p < 0.001). Comparison of total nerve area showed no statistical significance. At this dose, IL-10 evaluated at 8 weeks was not significantly different than placebo in functional, NCVs, and most morphological measures. However, there was a significant difference in thicker myelin sheaths and higher myelination index and lower collagen levels. This suggests that future experiments of IL-10 at different doses or longer periods of evaluation would be of interest.