Antibody-mediated rejection (ABMR) can occur in patients with preexisting anti-HLA donor-specific antibodies (DSA) or in patients who develop
DSA. However, how these processes compare in terms of ...allograft injury and outcome has not been addressed. From a cohort of 771 kidney biopsy specimens from two North American and five European centers, we performed a systematic assessment of clinical and biologic parameters, histopathology, circulating DSA, and allograft gene expression for all patients with ABMR (
=205). Overall, 103 (50%) patients had preexisting DSA and 102 (50%) had
DSA. Compared with patients with preexisting DSA ABMR, patients with
DSA ABMR displayed increased proteinuria, more transplant glomerulopathy lesions, and lower glomerulitis, but similar levels of peritubular capillaritis and C4d deposition.
DSA ABMR was characterized by increased expression of IFN
-inducible, natural killer cell, and T cell transcripts, but less expression of AKI transcripts compared with preexisting DSA ABMR. The preexisting DSA ABMR had superior graft survival compared with the
DSA ABMR (63% versus 34% at 8 years after rejection, respectively;
<0.001). After adjusting for clinical, histologic, and immunologic characteristics and treatment, we identified
DSA ABMR (hazard ratio HR, 1.82 compared with preexisting DSA ABMR; 95% confidence interval 95% CI, 1.07 to 3.08;
=0.03); low eGFR (<30 ml/min per 1.73 m
) at diagnosis (HR, 3.27; 95% CI, 1.48 to 7.23;
<0.001); ≥0.30 g/g urine protein-to-creatinine ratio (HR, 2.44; 95% CI, 1.47 to 4.09;
<0.001); and presence of cg lesions (HR, 2.25; 95% CI, 1.34 to 3.79;
=0.002) as the main independent determinants of allograft loss. Our findings support the transplant of kidneys into highly sensitized patients and should encourage efforts to monitor patients for
DSA.
Disordered coagulation contributes to death in sepsis and lacks effective treatments. Existing markers of disseminated intravascular coagulation (DIC) reflect its sequelae rather than its causes, ...delaying diagnosis and treatment. Here we show that disruption of the endothelial Tie2 axis is a sentinel event in septic DIC. Proteomics in septic DIC patients revealed a network involving inflammation and coagulation with the Tie2 antagonist, angiopoietin-2 (Angpt-2), occupying a central node. Angpt-2 was strongly associated with traditional DIC markers including platelet counts, yet more accurately predicted mortality in 2 large independent cohorts (combined N = 1,077). In endotoxemic mice, reduced Tie2 signaling preceded signs of overt DIC. During this early phase, intravital imaging of microvascular injury revealed excessive fibrin accumulation, a pattern remarkably mimicked by Tie2 deficiency even without inflammation. Conversely, Tie2 activation normalized prothrombotic responses by inhibiting endothelial tissue factor and phosphatidylserine exposure. Critically, Tie2 activation had no adverse effects on bleeding. These results mechanistically implicate Tie2 signaling as a central regulator of microvascular thrombus formation in septic DIC and indicate that circulating markers of the Tie2 axis could facilitate earlier diagnosis. Finally, interventions targeting Tie2 may normalize coagulation in inflammatory states while averting the bleeding risks of current DIC therapies.
Abstract Alzheimer's disease (AD) is a progressive neurodegenerative disease characterized by deposits of amyloid-β and neurofibrillary tangles. It has been suggested that inflammatory changes are ...associated with disease; however, it has not been established whether these are a consequence of ongoing neurodegeneration or whether inflammation itself contributes to disease pathogenesis. Recent studies suggest that exposure to infection can accelerate cognitive decline in AD patients, and pathogens have been detected in the AD brain. However, the influence of infection on neuroinflammation and pathology remains poorly understood. In this study, we examined the effect of a peripheral infection on AD pathology in APP/PS1 mice. We found that, 8 weeks after infection with the Gram negative respiratory pathogen Bordetella pertussis , there was significant infiltration of IFNγ- and IL-17–producing T cells and NKT cells in older APP/PS1 mice. This was accompanied by increased glial activation and amyloid-β deposition. The data suggest that infection is a critical factor in the progression of AD, emphasising the importance of early diagnosis and treatment of infections in elderly individuals.
The NOD-like receptor (NLR) family, pyrin domain-containing protein 3 (NLRP3) inflammasome is a component of the inflammatory process, and its aberrant activation is pathogenic in inherited disorders ...such as cryopyrin-associated periodic syndrome (CAPS) and complex diseases such as multiple sclerosis, type 2 diabetes, Alzheimer's disease and atherosclerosis. We describe the development of MCC950, a potent, selective, small-molecule inhibitor of NLRP3. MCC950 blocked canonical and noncanonical NLRP3 activation at nanomolar concentrations. MCC950 specifically inhibited activation of NLRP3 but not the AIM2, NLRC4 or NLRP1 inflammasomes. MCC950 reduced interleukin-1β (IL-1β) production in vivo and attenuated the severity of experimental autoimmune encephalomyelitis (EAE), a disease model of multiple sclerosis. Furthermore, MCC950 treatment rescued neonatal lethality in a mouse model of CAPS and was active in ex vivo samples from individuals with Muckle-Wells syndrome. MCC950 is thus a potential therapeutic for NLRP3-associated syndromes, including autoinflammatory and autoimmune diseases, and a tool for further study of the NLRP3 inflammasome in human health and disease.
Celotno besedilo
Dostopno za:
DOBA, IJS, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SBMB, UILJ, UKNU, UL, UM, UPUK
Ligands of the endothelial-enriched tunica interna endothelial cell kinase 2 (Tie2) are markedly imbalanced in severe infections associated with vascular leakage, yet regulation of the receptor ...itself has been understudied in this context. Here, we show that TIE2 gene expression may constitute a novel vascular barrier control mechanism in diverse infections. Tie2 expression declined rapidly in wide-ranging models of leak-associated infections, including anthrax, influenza, malaria, and sepsis. Forced Tie2 suppression sufficed to attenuate barrier function and sensitize endothelium to permeability mediators. Rapid reduction of pulmonary Tie2 in otherwise healthy animals attenuated downstream kinase signaling to the barrier effector vascular endothelial (VE)-cadherin and induced vascular leakage. Compared with wild-type littermates, mice possessing one allele of Tie2 suffered more severe vascular leakage and higher mortality in two different sepsis models. Common genetic variants that influence TIE2 expression were then sought in the HapMap3 cohort. Remarkably, each of the three strongest predicted cis-acting SNPs in HapMap3 was also associated with the risk of acute respiratory distress syndrome (ARDS) in an intensive care unit cohort of 1,614 subjects. The haplotype associated with the highest TIE2 expression conferred a 28% reduction in the risk of ARDS independent of other major clinical variables, including disease severity. In contrast, the most common haplotype was associated with both the lowest TIE2 expression and 31% higher ARDS risk. Together, the results implicate common genetic variation at the TIE2 locus as a determinant of vascular leak-related clinical outcomes from common infections, suggesting new tools to identify individuals at unusual risk for deleterious complications of infection.
Stimulation of protease-activated receptor 1 (PAR1) on endothelium by activated protein C (APC) is protective in several animal models of disease, and APC has been used clinically in severe sepsis ...and wound healing. Clinical use of APC, however, is limited by its immunogenicity and its anticoagulant activity. We show that a class of small molecules termed “parmodulins” that act at the cytosolic face of PAR1 stimulates APC-like cytoprotective signaling in endothelium. Parmodulins block thrombin generation in response to inflammatory mediators and inhibit platelet accumulation on endothelium cultured under flow. Evaluation of the antithrombotic mechanism showed that parmodulins induce cytoprotective signaling through Gβγ, activating a PI3K/Akt pathway and eliciting a genetic program that includes suppression of NF-κB–mediated transcriptional activation and up-regulation of select cytoprotective transcripts. STC1 is among the up-regulated transcripts, and knockdown of stanniocalin-1 blocks the protective effects of both parmodulins and APC. Induction of this signaling pathway in vivo protects against thromboinflammatory injury in blood vessels. Small-molecule activation of endothelial cytoprotection through PAR1 represents an approach for treatment of thromboinflammatory disease and provides proof-of-principle for the strategy of targeting the cytoplasmic surface of GPCRs to achieve pathway selective signaling.
Whooping cough caused by Bordetella pertussis is a re-emerging infectious disease despite the introduction of safer acellular pertussis vaccines (Pa). One explanation for this is that Pa are less ...protective than the more reactogenic whole cell pertussis vaccines (Pw) that they replaced. Although Pa induce potent antibody responses, and protection has been found to be associated with high concentrations of circulating IgG against vaccine antigens, it has not been firmly established that host protection induced with this vaccine is mediated solely by humoral immunity. The aim of this study was to examine the relative contribution of Th1 and Th17 cells in host immunity to infection with B. pertussis and in immunity induced by immunization with Pw and Pa and to use this information to help rationally design a more effective Pa. Our findings demonstrate that Th1 and Th17 both function in protective immunity induced by infection with B. pertussis or immunization with Pw. In contrast, a current licensed Pa, administered with alum as the adjuvant, induced Th2 and Th17 cells, but weak Th1 responses. We found that IL-1 signalling played a central role in protective immunity induced with alum-adsorbed Pa and this was associated with the induction of Th17 cells. Pa generated strong antibody and Th2 responses, but was fully protective in IL-4-defective mice, suggesting that Th2 cells were dispensable. In contrast, Pa failed to confer protective immunity in IL-17A-defective mice. Bacterial clearance mediated by Pa-induced Th17 cells was associated with cell recruitment to the lungs after challenge. Finally, protective immunity induced by an experimental Pa could be enhanced by substituting alum with a TLR agonist that induces Th1 cells. Our findings demonstrate that alum promotes protective immunity through IL-1β-induced IL-17A production, but also reveal that optimum protection against B. pertussis requires induction of Th1, but not Th2 cells.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The physiological effect of complex mixtures of anthropogenic contaminants on aquatic organisms is not well understood. This study employed a suite of sub-cellular biomarkers and general health ...measurements to assess the effect of urban-derived contaminants on wild freshwater mussels. Adult Lasmigona costata were collected from four sites in the Grand River (ON, Canada) that receive incremental amounts of municipal wastewater effluents and road runoff. Biomarkers of metal exposure, oxidative stress, and general health were examined in the gills of wild mussels. Concentrations of nine metals as well as the metal-binding protein, metallothionein (MT), were significantly higher (p<0.05) in mussels living downstream of the urban area. For example the concentrations of Pb, Cr and Zn were five-fold, and Ag more than 20 fold higher in mussels collected downstream of 11 municipal wastewater treatment plants and four cities compared to levels in upstream mussels. Downstream mussels showed evidence of oxidative stress, such that lipid peroxidation (LPO) (as thiobarbiturate reactive substances) was significantly elevated and the antioxidant capacity against peroxyl radicals (ACAP) was significantly decreased (p<0.01) in downstream mussels compared to upstream mussels. Regarding general health indicators, although gill lipid concentrations were similar across sites, protein concentration was significantly (p<0.001) higher in mussels collected from the upstream reference site compared to all downstream sites. The trends observed indicate that there are physiological effects in mussels associated with chronic exposure to complex urban inputs and that some biomarkers respond to municipal wastewater effluent and road runoff exposure in a cumulative manner. The observed oxidative stress response (ACAP) along with the elevation in MT, suggest that even though the defense mechanisms in the chronically exposed mussels have been activated, there is still an excess of reactive oxygen species that result in oxidative damage. The physiological effects of exposure reported in this study correspond with previously reported whole-organism impacts and declines in freshwater mussel populations in the urban-impacted region of this watershed.
•Elevated tissue metals and metallothionein in wild mussels downstream of urban area.•Antioxidant capacity depressed in downstream mussels.•Biomarkers responded cumulatively to municipal wastewater effluents and urban runoff.•Biomarker responses correspond to negative effects at organism and population level.
Cerebral malaria is a leading cause of global morbidity and mortality. Interventions targeting the underlying pathophysiology of cerebral malaria may improve outcomes compared to treatment with ...antimalarials alone. Microvascular leak plays an important role in the pathogenesis of cerebral malaria. The angiopoietin (Ang)-Tie-2 system is a critical regulator of vascular function. We show that Ang-1 expression and soluble Tie-2 expression were associated with disease severity and outcome in a prospective study of Ugandan children with severe malaria and in a preclinical murine model of experimental cerebral malaria. Ang-1 was necessary for maintenance of vascular integrity and survival in a mouse model of cerebral malaria. Therapeutic administration of Ang-1 preserved blood-brain barrier integrity and, in combination with artesunate treatment, improved survival beyond that with artesunate alone. These data define a role for dysregulation of the Ang-Tie-2 axis in the pathogenesis of cerebral malaria and support the evaluation of Ang-Tie-2-based interventions as potential adjunctive therapies for treating severe malaria.
Whole cell pertussis vaccines (Pw) induce Th1 responses and protect against Bordetella pertussis infection, whereas pertussis acellular vaccines (Pa) induce Ab and Th2-biased responses and also ...protect against severe disease. In this study, we show that Pw failed to generate protective immunity in TLR4-defective C3H/HeJ mice. In contrast, protection induced with Pa was compromised, but not completely abrogated, in C3H/HeJ mice. Immunization with Pw, but not Pa, induced a population of IL-17-producing T cells (Th-17), as well as Th1 cells. Ag-specific IL-17 and IFN-gamma production was significantly lower in Pw-immunized TLR4-defective mice. Furthermore, treatment with neutralizing anti-IL-17 Ab immediately before and after B. pertussis challenge significantly reduced the protective efficacy of Pw. Stimulation of dendritic cells (DC) with Pw promoted IL-23, IL-12, IL-1beta, and TNF-alpha production, which was impaired in DC from TLR4-defective mice. B. pertussis LPS, which is present in high concentrations in Pw, induced IL-23 production by DC, which enhanced IL-17 secretion by T cells, but the induction of Th-17 cells was also dependent on IL-1. In addition, we identified a new effector function for IL-17, activating macrophage killing of B. pertussis, and this bactericidal activity was less efficient in macrophages from TLR4-defective mice. These data provide the first definitive evidence of a role for TLRs in protective immunity induced by a human vaccine. Our findings also demonstrate that activation of innate immune cells through TLR4 helps to direct the induction of Th1 and Th-17 cells, which mediate protective cellular immunity to B. pertussis.
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