The introduction of transcatheter aortic valve replacement mandates attention to outcomes after surgical aortic valve replacement (SAVR) in low-risk, intermediate-risk, and very high-risk patients.
...The study population included 141,905 patients who underwent isolated primary SAVR from 2002 to 2010. Patients were risk-stratified by Society of Thoracic Surgeons (STS) predicted risk of mortality (PROM) <4% (group 1, n = 113,377), 4% to 8% (group 2, n = 19,769), and >8% (group 3, n = 8,759). The majority of patients were considered at low risk (80%), and only 6.2% were categorized as being at high risk. Outcomes were analyzed based on two time periods: 2002 to 2006 (n = 63,754) and 2007 to 2010 (n = 78,151).
The mean age was 65 years in group 1, 77 in group 2, and 77 in group 3 (p < 0.0001). The median STS PROM for the entire population was 1.84: 1.46% in group 1, 5.24% in group 2, and 11.2% in group 3 (p < 0.0001). Compared with PROM, in-hospital mean mortality was lower than expected in all patients (2.5% vs 2.95%) and when analyzed within risk groups was as follows: group 1 (1.4% vs 1.7%), group 2 (5.1% vs 5.5%), and group 3 (11.8% vs 13.7%) (p < 0.0001). In the most recent surgical era, operative mortality was significantly reduced in group 2 (5.4% vs 6.4%, p = 0.002) and group 3 (11.9% vs 14.4%, p = 0.0004) but not in group 1.
Nearly 80% of patients undergoing SAVR have outcomes that are superior to those by the predicted risk models. In the most recent era, early results have further improved in medium-risk and high-risk patients. This large real-world assessment serves as a benchmark for patients with aortic valve stenosis as therapeutic options are further evaluated.
•Most mouse dermal γδ T cells are IL-17+, CCR6+, motile, and Vγ4Vδ4+ or Vγ6Vδ1+.•They are pathogenic in psoriasis, but enhance protection against some pathogens.•They also enhance CD4+ αβ T ...cell-mediated immunity.•Human dermal γδ T cells are analogous in producing IL-17 and exacerbating psoriasis.•Responses by dermal γδ T cells can be triggered without the addition of antigen.
Over the last several years, a number of papers have called attention to a distinct population of γδ T cells preferentially found in the dermis of the skin of normal mice. These cells appear to play an important role in promoting the development of psoriasis, but also are critical for host resistance to particular pathogens. They are characterized by the expression of a limited subset of γδ T cell receptors and a strong propensity to secrete IL-17. Perhaps most importantly, humans appear to carry an equivalent dermal γδ T cell population, likewise biased to secrete IL-17 and also implicated as playing a pathogenic role in psoriasis. This review will attempt to summarize and reconcile recent findings concerning the dermal γδ T cells.
During pregnancy, changes occur to influence the maternal gut microbiome, and potentially the fetal microbiome. Diet has been shown to impact the gut microbiome. Little research has been conducted ...examining diet during pregnancy with respect to the gut microbiome. To meet inclusion criteria, dietary analyses must have been conducted as part of the primary aim. The primary outcome was the composition of the gut microbiome (infant or maternal), as assessed using culture-independent sequencing techniques. This review identified seven studies for inclusion, five examining the maternal gut microbiome and two examining the fetal gut microbiome. Microbial data were attained through analysis of stool samples by 16S ribosomal RNA gene-based microbiota assessment. Studies found an association between the maternal diet and gut microbiome. High-fat diets (% fat of total energy), fat-soluble vitamins (mg/d) and fibre (g/d) were the most significant nutrients associated with the gut microbiota composition of both neonates and mothers. High-fat diets were significantly associated with a reduction in microbial diversity. High-fat diets may reduce microbial diversity, while fibre intake may be positively associated with microbial diversity. The results of this review must be interpreted with caution. The number of studies was low, and the risk of observational bias and heterogeneity across the studies must be considered. However, these results show promise for dietary intervention and microbial manipulation in order to favour an increase of health-associated taxa in the gut of the mother and her offspring.
The γδ T cells play an important role in both mice and humans as a source of the cytokine IL‐17, which is key for immune resistance to certain pathogens. In mice, most of these IL‐17 producers, ...termed γδT‐17 cells, actually comprise two distinct types: those expressing an invariant Vγ6Vδ1+ TCR and those expressing a Vγ4+ TCR. Murine γδT‐17 cells acquire an inherent bias to produce IL‐17 and other “type 17” cytokines during thymic development. The similarities and differences between the two mouse γδT‐17 types are reviewed here, and the potential implications of their differences are discussed. There is some evidence that two distinct TCR‐defined IL‐17‐producing γδ T cell subsets also exist in humans, but unlike the mouse γδT‐17 cells, these cells are probably not imprinted with an IL‐17 bias during thymic development, but rather acquire an IL‐17 bias in the periphery.
We previously reported that activated γδ T cells greatly enhance autoimmune responses, particularly the Th17 response. To determine the mechanisms involved, we made a series of comparisons between ...activated and non-activated γδ T cells. Our results showed that activated γδ T cells expressed greatly increased levels of A2A adenosine receptor (A2AR) and decreased amounts of CD73, as well as increased amounts of T cell activation markers such as CD69, CD44 and CD25. We show that A2AR is a major functional molecule in the enhancing activity of γδ T cells. A2AR-/- γδ T cells (isolated from A2AR-/- mouse), lost their Th17-enhancing activity as did A2AR+/+ γδ T cells (isolated from wt-B6 mouse) after treatment with an A2AR antagonist. Since γδ T cells possess either an enhancing or an inhibiting effect, we also tested whether A2AR expression on γδ T cells is essential to their inhibiting effect. Our results showed that the inhibiting effect of A2AR-/- γδ T cells was as potent as that of A2AR+/+ γδ T cells. In a previous report we showed that the expression of different levels of CD73 molecule allowed γδ T cells to adjust their suppressive activity; in the current study, we show that expression of increased amounts of A2AR allows γδ T cells to more effectively exert their enhancing function.
γδ T cells: an important source of IL-17 Roark, Christina L; Simonian, Philip L; Fontenot, Andrew P ...
Current opinion in immunology,
06/2008, Letnik:
20, Številka:
3
Journal Article
Recenzirano
Odprti dostop
IL-17 is a cytokine that plays an important role in orchestrating innate immune function. In addition, IL-17 has been shown to exacerbate autoimmune diseases. CD4+ αβ T cells, γδ T cells, and NK ...cells all produce IL-17. Th17 cells are a newly defined αβ+ T cell lineage characterized by IL-17 production. However, γδ T cells are often the major source of this cytokine. Their response can be very rapid during bacterial infections and has been shown to be protective, but IL-17-producing γδ T cells have also been found to exacerbate collagen-induced arthritis. Interestingly, some γδ T cells produce IL-17 in response to IL-23 alone, even in naïve animals, suggesting they are already differentiated and may develop differently than CD4+ αβ Th17 cells.
Hypersensitivity pneumonitis is an environmental lung disease characterized by a diffuse mononuclear cell infiltrate in the lung that can progress to pulmonary fibrosis with chronic exposure to an ...inhaled Ag. Using a well-established murine model of hypersensitivity pneumonitis, we repeatedly exposed C57BL/6 mice to Saccharopolyspora rectivirgula to investigate whether T cells are required for lung fibrosis. In the absence of alphabeta T cells, TCRbeta(-/-) mice exposed to S. rectivirgula for 4 wk had markedly decreased mononuclear infiltrates and collagen deposition in the lung compared with wild-type C57BL/6 mice. In contrast to CD8(+) T cells, adoptive transfer of CD4(+) T cells reconstituted the S. rectivirgula-induced inflammatory and fibrotic response, suggesting that the CD4(+) T cell represents the critical alphabeta T cell subset. Cytokine analysis of lung homogenates at various time points after S. rectivirgula exposure failed to identify a predominant Th1 or Th2 phenotype. Conversely, IL-17 was found in the lung at increasing concentrations with continued exposure to S. rectivirgula. Intracellular cytokine staining revealed that 14% of CD4(+) T cells from the lung of mice treated with S. rectivirgula expressed IL-17A. In the absence of IL-17 receptor signaling, Il17ra(-/-) mice had significantly decreased lung inflammation and fibrosis compared with wild-type C57BL/6 mice. These data are the first to demonstrate an important role for Th17-polarized CD4(+) T lymphocytes in the immune response directed against S. rectivirgula in this murine model of hypersensitivity pneumonitis and pulmonary fibrosis.
Whether γδ T cells inhibit or enhance the Foxp3 T cell response depends upon their activation status. The critical enhancing effector in the supernatant is adenosine. Activated γδ T cells express ...adenosine receptors at high levels, which enables them to deprive Foxp3+ T cells of adenosine, and to inhibit their expansion. Meanwhile, cell-free supernatants of γδ T cell cultures enhance Foxp3 T cell expansion. Thus, inhibition and enhancement by γδ T cells of Foxp3 T cell response are a reflection of the balance between adenosine production and absorption by γδ T cells. Non-activated γδ T cells produce adenosine but bind little, and thus enhance the Foxp3 T cell response. Activated γδ T cells express high density of adenosine receptors and have a greatly increased ability to bind adenosine. Extracellular adenosine metabolism and expression of adenosine receptor A2ARs by γδ T cells played a major role in the outcome of γδ and Foxp3 T cell interactions. A better understanding of the functional conversion of γδ T cells could lead to γδ T cell-targeted immunotherapies for related diseases.
Like B cells, T cells can be immortalized through hybridization with lymphoma cells, a technique that has been particularly useful in the study of the T cell receptors (TCR) for antigen. In T cell ...hybridizations, the AKR mouse strain-derived thymus lymphoma BW5147 is by far the most popular fusion line. However, the full potential of this technology had to await inactivation of the productively rearranged TCR-α and -β genes in the lymphoma. BWα-β-, the TCR-gene deficient variant of the original lymphoma, which has become the fusion line of choice for αβ T cells, is now available with numerous modifications, enabling the investigation of many aspects of TCR-mediated responses and TCR-structure. Unexpectedly, inactivating BW’s functional TCR-α gene also rendered the lymphoma more permissive for the expression of TCR-γδ, facilitating the study of γδ T cells, their TCRs, and their TCR-mediated reactivity.
γδ T cells can either enhance or inhibit an adaptive immune response, but the mechanisms involved are not fully understood. Given that CD73 is the main enzyme responsible for conversion of AMP into ...the immunosuppressive molecule adenosine, we investigated its role in the regulatory function of γδ T cells in experimental autoimmune uveitis (EAU). We found that γδ T cells expressed different amounts of CD73 during the different stages of EAU and that low CD73 expression on γδ T cells correlated with enhanced Th17 response-promoting activity. Functional comparison of CD73-deficient and wild-type B6 (CD73+/+) mice showed that failure to express CD73 decreased both the enhancing and suppressive effects of γδ T cells on EAU. We also demonstrated that γδ T cells expressed different amounts of CD73 when activated by different pathways, which enabled them to either enhance or inhibit an adaptive immune response. Our results demonstrate that targeting CD73 expression on γδ T cells may allow us to manipulate their pro- or anti-inflammatory effect on Th17 responses.
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