BACKGROUND—Inflammation within atherosclerotic lesions contributes to plaque instability and vulnerability to rupture. We set out to evaluate the use of a macrophage labeling agent to identify ...carotid plaque inflammation by in vivo magnetic resonance imaging (MRI).
METHODS AND RESULTS—Thirty patients with symptomatic severe carotid stenosis scheduled for carotid endarterectomy underwent multi-sequence MRI of the carotid bifurcation before and after injection of ultrasmall superparamagnetic particles of iron oxide (USPIOs). USPIO particles accumulated in macrophages in 24 of 30 plaques (80%). Areas of signal intensity reduction, corresponding to USPIO/macrophage-positive histological sections, were visualized in 24 of 27 (89%) patients, with an average reduction in signal intensity induced by the USPIO particles of 24% (range, 3.1% to 60.8%).
CONCLUSIONS—USPIO-enhanced MRI can identify plaque inflammation in vivo by accumulation of USPIO within macrophages in carotid plaques.
Background- It has been suggested that inflammatory cells within vulnerable plaques may be visualized by superparamagnetic iron oxide particle-enhanced MRI. The purpose of this study was to determine ...the time course for macrophage visualization with in vivo contrast-enhanced MRI using an ultrasmall superparamagnetic iron oxide (USPIO) agent in symptomatic human carotid disease.
Eight patients scheduled for carotid endarterectomy underwent multisequence MRI of the carotid bifurcation before and 24, 36, 48, and 72 hours after Sinerem (2.6 mg/kg) infusion.
USPIO particles accumulated in macrophages in 7 of 8 patients given Sinerem. Areas of signal intensity reduction, corresponding to USPIO/macrophage-positive histological sections, were visualized in all 7 of these patients, optimally between 24 and 36 hours, decreasing after 48 hours, but still evident up to 96 hours after infusion.
USPIO-enhanced MRI of carotid atheroma can be used to identify macrophages in vivo. The temporal change in the resultant signal intensity reduction on MRI suggests an optimal time window for the detection of macrophages on postinfusion imaging.
Different profiles of alloantibody responses are observed in the clinic, with those that persist, often despite targeted treatment, associated with poorer long-term transplant outcomes. Although such ...responses would suggest an underlying germinal center (GC) response, the relationship to cellular events within the allospecific B cell population is unclear. Here we examine the contribution of germinal center (GC) humoral alloimmunity to chronic antibody mediated rejection (AMR). A murine model of chronic AMR was developed in which T cell deficient (
) C57BL/6 recipients were challenged with MHC-mismatched BALB/c heart allografts and T cell help provided by reconstituting with 10
"TCR75" CD4 T cells that recognize self-restricted allopeptide derived from the H-2K
MHC class I alloantigen. Reconstituted recipients developed Ig-switched anti-K
alloantibody responses that were slow to develop, but long-lived, with confocal immunofluorescence and flow cytometric characterization of responding H-2K
-allospecific B cells confirming persistent splenic GC activity. This was associated with T follicular helper (T
) cell differentiation of the transferred TCR75 CD4 T cells. Heart grafts developed progressive allograft vasculopathy, and were rejected chronically (MST 50 days), with explanted allografts displaying features of humoral vascular rejection. Critically, late alloantibody responses were abolished, and heart grafts survived indefinitely, in recipients reconstituted with
TCR75 CD4 T cells that were genetically incapable of providing T
cell function. The GC response was associated with affinity maturation of the anti-K
alloantibody response, and its contribution to progression of allograft vasculopathy related principally to secretion of alloantibody, rather than to enhanced alloreactive T cell priming, because grafts survived long-term when B cells could present alloantigen, but not secrete alloantibody. Similarly, sera sampled at late time points from chronically-rejecting recipients induced more vigorous donor endothelial responses
than sera sampled earlier after transplantation. In summary, our results suggest that chronic AMR and progression of allograft vasculopathy is dependent upon allospecific GC activity, with critical help provided by T
cells. Clinical strategies that target the T
cell subset may hold therapeutic potential. This work is composed of two parts, of which this is Part II. Please read also Part I: Alsughayyir et al., 2019.
Humoral alloimmunity is now recognized as a major determinant of transplant outcome. MHC glycoprotein is considered a typical T-dependent antigen, but the nature of the T cell alloresponse that ...underpins alloantibody generation remains poorly understood. Here, we examine how the relative frequencies of alloantigen-specific B cells and helper CD4 T cells influence the humoral alloimmune response and how this relates to antibody-mediated rejection (AMR). An MHC-mismatched murine model of cardiac AMR was developed, in which T cell help for alloantibody responses in T cell deficient (
) C57BL/6 recipients against donor H-2K
MHC class I alloantigen was provided by adoptively transferred "TCR75" CD4 T cells that recognize processed H-2K
allopeptide via the indirect-pathway. Transfer of large numbers (5 × 10
) of TCR75 CD4 T cells was associated with rapid development of robust class-switched anti-H-2K
humoral alloimmunity and BALB/c heart grafts were rejected promptly (MST 9 days). Grafts were not rejected in T and B cell deficient
recipients that were reconstituted with TCR75 CD4 T cells or in control (non-reconstituted)
recipients, suggesting that the transferred TCR75 CD4 T cells were mediating graft rejection principally by providing help for effector alloantibody responses. In support, acutely rejecting BALB/c heart grafts exhibited hallmark features of acute AMR, with widespread complement C4d deposition, whereas cellular rejection was not evident. In addition, passive transfer of immune serum from rejecting mice to
recipients resulted in eventual BALB/c heart allograft rejection (MST 20 days). Despite being long-lived, the alloantibody responses observed at rejection of the BALB/c heart grafts were predominantly generated by extrafollicular foci: splenic germinal center (GC) activity had not yet developed; IgG secreting cells were confined to the splenic red pulp and bridging channels; and, most convincingly, rapid graft rejection still occurred when recipients were reconstituted with similar numbers of
TCR75 CD4 T cells that are genetically incapable of providing T follicular helper cell function for generating GC alloimmunity. Similarly, alloantibody responses generated in
recipients reconstituted with smaller number of wild-type TCR75 CD4 T cells (10
), although long-lasting, did not have a discernible extrafollicular component, and grafts were rejected much more slowly (MST 50 days). By modeling antibody responses to Hen Egg Lysozyme protein, we confirm that a high ratio of antigen-specific helper T cells to B cells favors development of the extrafollicular response, whereas GC activity is favored by a relatively high ratio of B cells. In summary, a relative abundance of helper CD4 T cells favors development of strong extrafollicular alloantibody responses that mediate acute humoral rejection, without requirement for GC activity. This work is composed of two parts, of which this is Part I. Please read also Part II: Chhabra et al., 2019.
ACE2 is a novel homologue of angiotensin converting enzyme (ACE). ACE2 is highly expressed in human heart and animal data suggest that ACE2 is an essential regulator of cardiac function in vivo. ...Since overactivity of the renin-angiotensin system contributes to the progression of heart failure, this investigation assessed changes in gene expression of ACE2, ACE, AT1 receptor and renin in the human failing heart.
The sensitive technique of quantitative reverse transcriptase polymerase chain reaction was used to determine the level of mRNA expression of ACE and ACE2 in human ventricular myocardium from donors with non-diseased hearts (n = 9), idiopathic dilated cardiomyopathy (IDC, n = 11) and ischemic cardiomyopathy (ICM, n = 12). Following logarithmic transformation of the data, a one-way analysis of variance was performed for each target gene followed by a Dunnett's test to compare the two disease groups IDC and ICM versus control.
As anticipated, ACE mRNA was found to be significantly increased in the failing heart with a 3.1 and 2.4-fold up-regulation found in IDC and ICM relative to non-diseased myocardium. Expression of ACE2 mRNA was also significantly up-regulated in IDC (2.4-fold increase) and ICM (1.8-fold increase) versus non-diseased myocardium. No change in angiotensin AT1 receptor mRNA expression was found in failing myocardium and renin mRNA was not detected.
These data suggest that ACE2 is up-regulated in human IDC and ICM and are consistent with the hypothesis that differential regulation of this enzyme may have important functional consequences in heart failure. This strengthens the hypothesis that ACE2 may be a relevant target for the treatment of heart failure and will hopefully spur further studies to clarify the functional effects in human myocardium of ACE2 derived peptides.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The development of humoral autoimmunity following organ transplantation is increasingly recognised, but of uncertain significance. We examine whether autoimmunity contributes independently to ...allograft rejection.
In a MHC class II-mismatched murine model of chronic humoral rejection, we report that effector antinuclear autoantibody responses were initiated upon graft-versus-host allorecognition of recipient B cells by donor CD4 T-cells transferred within heart allografts. Consequently, grafts were rejected more rapidly, and with markedly augmented autoantibody responses, upon transplantation of hearts from donors previously primed against recipient. Nevertheless, rejection was dependent upon recipient T follicular helper (TFH) cell differentiation and provision of cognate (peptide-specific) help for maintenance as long-lived GC reactions, which diversified to encompass responses against vimentin autoantigen. Heart grafts transplanted into stable donor/recipient mixed haematopoietic chimeras, or from parental strain donors into F1 recipients (neither of which can trigger host adaptive alloimmune responses), nevertheless provoked GC autoimmunity and were rejected chronically, with rejection similarly dependent upon host TFH cell differentiation.
Thus, autoantibody responses contribute independently of host adaptive alloimmunity to graft rejection, but require host TFH cell differentiation to maintain long-lived GC responses. The demonstration that one population of helper CD4 T-cells initiates humoral autoimmunity, but that a second population of TFH cells is required for its maintenance as a GC reaction, has important implications for how autoimmune-related phenomena manifest.
•Passenger donor CD4 T cells in heart grafts initiate recipient humoral autoimmunity.•Secondary host T follicular helper (TFH) cell differentiation maintains the response.•Germinal center (GC) autoimmunity results in intermolecular epitope diversification.•GC autoimmunity independently mediates allograft rejection.•Transfer of host TFH cells triggers GC autoimmunity in secondary recipients.
Bladder cancer patients suffer significant treatment failure, including high rates of recurrence and poor outcomes for advanced disease. If mechanisms to improve tumour cell treatment sensitivity ...could be identified and/or if tumour response could be predicted, it should be possible to improve local‐control and survival. Previously, we have shown that radiation‐induced DNA damage, measured by alkaline Comet assay (ACA), correlates bladder cancer cell radiosensitivity in vitro. In this study we first show that modified‐ACA measures of cisplatin and mitomycin‐C‐induced damage also correlate bladder cancer cell chemosensitivity in vitro, with essentially the same rank order for chemosensitivity as for radiosensitivity. Furthermore, ACA studies of radiation‐induced damage in different cell‐DNA substrates (nuclei, nucleoids and intact parent cells) suggest that it is a feature retained in the prepared nucleoids that is responsible for the relative damage sensitivity of bladder cancer cells, suggestive of differences in the organisation of DNA within resistant vs. sensitive cells. Second, we show that ACA analysis of biopsies from bladder tumours reveal that reduced DNA damage sensitivity associates with poorer treatment outcomes, notably that tumours with a reduced damage response show a significant association with local recurrence of non‐invasive disease and that reduced damage response was a better predictor of recurrence than the presence of high‐risk histology in this cohort. In conclusion, this study demonstrates that mechanisms governing treatment‐induced DNA damage are both central to and predictive of bladder cancer cell treatment sensitivity and exemplifies a link between DNA damage resistance and both treatment response and tumour aggression.
What's new?
Treatment failure in bladder cancer is associated with poor survival, so the ability to sensitize tumor cells to treatment or to predict tumor response could have major impacts on patient outcome. Here, alkaline Comet assay (ACA) measures of bladder cancer cell DNA damage caused by chemotherapy were correlated with in vitro cancer cell chemosensitivity. Furthermore, reduced ACA measures of ex vivo radiation‐induced damage was associated with poor treatment outcomes for non‐muscle invasive disease following resection, based on ACA analysis of bladder tumor biopsies. The findings suggest that there is a link between resistance to DNA damage and both tumor treatment response and tumor aggression in bladder cancer.
We report an inter-laboratory comparison of analytical laboratories involved in the quantification of polycyclic aromatic hydrocarbons (PAHs) collected by sampling organisations from industrial ...stacks (e.g. waste incinerators). Four reference solutions were prepared containing nominally 10 ng/ml, 50 ng/ml, 200 ng/ml and 500 ng/ml of naphthalene, benzoaanthracene, chrysene, benzobfluoranthene, benzokfluoranthene, benzoapyrene, indeno1,2,3-cdpyrene and dibenzoa,hanthracene prior to despatch to five analytical laboratories with quantification requested in accordance with ISO 11338-2. Across four of the laboratories (the 5th returned unusable data), significant deviations from the reference concentrations were found frequently in excess of the benchmarks of 37 %—from the validation data in ISO 11338-2—and 21 %—from the Environment Agency for England’s Monitoring Certification Scheme. Also, much of the variance was systemic in nature indicating a possible issue with the quality of some of the stock solutions used by the laboratories for calibration. Whilst more proficiency testing would be welcomed to monitor and improve performance, this should be provided in addition to more support for analytical laboratories. A key mechanism of support is the standards themselves and there is a timely opportunity in that ISO/TC 146/SC 1 are due to revise ISO 11338. Possible improvements include full validation of high performance liquid chromatography and gas chromatography–mass spectrometry methods (to better understand what performance can reasonably be expected from laboratories), a requirement to correct results to individual laboratory PAH extraction efficiency, and a required uncertainty stipulated for the overall method (also aiding setting pass/fail criteria for proficiency testing).
Food poisoning caused by
(campylobacteriosis) is the most prevalent bacterial disease associated with the consumption of poultry, beef, lamb and pork meat and unpasteurized dairy products. A variety ...of livestock industry, food chain and public health interventions have been implemented or proposed to reduce disease prevalence, some of which entail costs for producers and retailers. This paper describes a project that set out to summarize the natural science evidence base relevant to campylobacteriosis control in as policy-neutral terms as possible. A series of evidence statements are listed and categorized according to the nature of the underlying information. The evidence summary forms the appendix to this paper and an annotated bibliography is provided in the electronic supplementary material.
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