Drosophila parasitoids go to space: Unexpected effects of spaceflight on hosts and their parasitoids.

While fruit flies (Drosophila melanogaster) and humans exhibit immune system dysfunction in space, studies examining their immune systems' interactions with natural parasites in space are lacking. Drosophila parasitoid wasps modify blood cell function to suppress host immunity. In this study, naive and parasitized ground and space flies from a tumor-free control and a blood tumor-bearing mutant strain were examined. Inflammation-related genes were activated in space in both fly strains. Whereas control flies did not develop tumors, tumor burden increased in the space-returned tumor-bearing mutants. Surprisingly, control flies were more sensitive to spaceflight than mutant flies; many of their essential genes were downregulated. Parasitoids appeared more resilient than fly hosts, and spaceflight did not significantly impact wasp survival or the expression of their virulence genes. Previously undocumented mutant wasps with novel wing color and wing shape were isolated post-flight and will be invaluable for host-parasite studies on Earth.

Platelet reactivity testing in peripheral artery disease.

PURPOSE: Oral antiplatelet therapy is routinely used to prevent adverse cardiovascular events in patients with peripheral artery disease (PAD). Several laboratory tests are available to quantify the degree of platelet inhibition following antiplatelet therapy. This article aims to provide a review of the literature surrounding platelet functional testing in patients with PAD receiving oral P2Y12 inhibitors and to offer guidance to clinicians for the use and interpretation of these tests. SUMMARY: A literature search of PubMed and the Web of Science Core Collection database was conducted. All studies that performed platelet function testing and reported clinical outcomes in patients with PAD were included. Evaluation of the data suggests that, among the available testing strategies, the VerifyNow platelet reactivity unit (PRU) test is the most widely used. Despite numerous investigations attempting to define a laboratory threshold indicating suboptimal response to antiplatelet therapy, controversy exists about which PRU value best correlates with cardiovascular outcomes (ie, mortality, stent thrombosis, etc). In the PAD literature, the most commonly used PRU thresholds are 208 or higher and 235 or higher. Nonetheless, adjusting antiplatelet regimens based on suboptimal P2Y12 reactivity values has yet to be proven useful in reducing the incidence of adverse cardiovascular outcomes. This review examines platelet function testing in patients with PAD and discusses the interpretation and application of these tests when monitoring the safety and efficacy of P2Y12 inhibitors. CONCLUSION: Although platelet functional tests may be simple to use, clinical trials thus far have failed to show benefit from therapy adjustments based on test results. Clinicians should be cautioned against relying on this test result alone and should instead consider a combination of laboratory, clinical, and patient-specific factors when adjusting P2Y12 inhibitor therapy in clinical practice.

Discovery of aspirin-triggered eicosanoid-like mediators in a Drosophila metainflammation blood tumor model.

Epidemiologic studies have linked the use of aspirin to a decline in chronic inflammation that underlies many human diseases, including some cancers. Aspirin reduces the levels of cyclooxygenase-mediated pro-inflammatory prostaglandins, promotes the production of pro-resolution molecules, and triggers the production of anti-inflammatory electrophilic mono-oxygenated (EFOX) lipid mediators. We investigated the effects of aspirin in fruit fly models of chronic inflammation. Ectopic Toll/NF-κB and JAK/STAT signaling in mutant D. melanogaster results in overproliferation of hematopoietic blood progenitors resulting in the formation of granuloma-like tumors. Ectopic JAK-STAT signaling also leads to metabolic inflammation. We report that aspirin-treated mutant flies experience reduction in metabolic inflammation, mitosis, ectopic immune signaling, and macrophage infiltration. Moreover, these flies synthesize 13-HODE, and aspirin triggers 13-oxoODE (13-EFOX-L2) production. Providing the precursor of 13-HODE, linoleic acid, or performing targeted knockdown of the transcription factor STAT in inflammatory blood cells, boosts 13-EFOX-L2 levels while decreasing metabolic inflammation. Thus, hematopoietic cells regulate metabolic inflammation in flies, and their effects can be reversed by pharmaceutical or dietary intervention, suggesting deep phylogenetic conservation in the ability of animals to resolve inflammation and repair tissue damage. These findings can help identify novel treatment targets in humans.

Predicting Unbound Phenytoin Concentrations: Effects of Albumin Concentration and Kidney Dysfunction.

STUDY OBJECTIVE: Several methods are available to predict unbound (free) phenytoin concentrations in patients with hypoalbuminemia; however, predictive methods have not been evaluated in patients with concurrent hypoalbuminemia and kidney dysfunction or in patients with mild to moderate (estimated glomerular filtration rate [eGFR] 30-90 ml/min/1.73 m2 ) kidney dysfunction alone. Thus the objective was to evaluate the accuracy and precision of predictive methods to estimate free phenytoin concentrations in patients with varying albumin concentrations and/or kidney dysfunction. DESIGN: Retrospective chart review. SETTING: Large academic medical center. PATIENTS: A total of 344 patients with free and total phenytoin, albumin, and serum creatinine concentrations obtained between November 2012 and May 2017. MEASUREMENTS AND MAIN RESULTS: Free phenytoin concentrations were estimated in patients without kidney dysfunction using the Winter-Tozer, Anderson, Kane, and Cheng equations. For the analysis in patients with eGFR lower than 90 ml/min/1.73 m2 , free phenytoin concentrations were estimated using the Shiner-Tozer derivation with adjusted affinity coefficients (C = 0.15, 0.20, 0.25, and 0.30). For both analyses, accuracy of predictive methods was evaluated by P20, the proportion of estimations within 20% of the measured free phenytoin concentration. In 158 patients with normal kidney function/normal albumin concentrations, 73 with normal kidney function/hypoalbuminemia, or 47 with mild kidney dysfunction/normal albumin concentrations, the Anderson method had the highest accuracy (86%, 82%, and 92%, respectively) and highest precision compared with the other methods. In 47 patients with normal albumin concentrations and mild kidney dysfunction or 13 with moderate kidney dysfunction, the free fraction was unchanged, and total phenytoin concentrations accurately reflected free concentrations. In 17 patients with hypoalbuminemia and mild or 17 with moderate kidney dysfunction, the Winter-Tozer (67% and 50%, respectively) and the Anderson (56% and 67%, respectively) methods had the highest accuracy compared with other methods with significantly lower accuracy compared with patients with normal kidney function. In the 14 patients with severe kidney dysfunction and hypoalbuminemia, none of the coefficients had a P20 accuracy greater than 45%. CONCLUSION: In patients with normal albumin concentrations, with or without mild or moderate kidney dysfunction and not receiving a protein-binding displacer, the free fraction of phenytoin is unchanged, and it is not necessary to measure a free phenytoin concentration. Free phenytoin concentrations should be measured directly in patients with hypoalbuminemia and kidney dysfunction.

Prostaglandin E2 promotes features of replicative senescence in chronically activated human CD8+ T cells.

Prostaglandin E2 (PGE2), a pleiotropic immunomodulatory molecule, and its free radical catalyzed isoform, iso-PGE2, are frequently elevated in the context of cancer and chronic infection. Previous studies have documented the effects of PGE2 on the various CD4+ T cell functions, but little is known about its impact on cytotoxic CD8+ T lymphocytes, the immune cells responsible for eliminating virally infected and tumor cells. Here we provide the first demonstration of the dramatic effects of PGE2 on the progression of human CD8+ T cells toward replicative senescence, a terminal dysfunctional state associated multiple pathologies during aging and chronic HIV-1 infection. Our data show that exposure of chronically activated CD8+ T cells to physiological levels of PGE2 and iso-PGE2 promotes accelerated acquisition of markers of senescence, including loss of CD28 expression, increased expression of p16 cell cycle inhibitor, reduced telomerase activity, telomere shortening and diminished production of key cytotoxic and survival cytokines. Moreover, the CD8+ T cells also produced higher levels of reactive oxygen species, suggesting that the resultant oxidative stress may have further enhanced telomere loss. Interestingly, we observed that even chronic activation per se resulted in increased CD8+ T cell production of PGE2, mediated by higher COX-2 activity, thus inducing a negative feedback loop that further inhibits effector function. Collectively, our data suggest that the elevated levels of PGE2 and iso-PGE2, seen in various cancers and HIV-1 infection, may accelerate progression of CD8+ T cells towards replicative senescence in vivo. Inhibition of COX-2 activity may, therefore, provide a strategy to counteract this effect.

Accelerated aging in HIV/AIDS: novel biomarkers of senescent human CD8+ T cells.

Clinical evaluation of immune reconstitution and health status during HIV-1 infection and anti-retroviral therapy (ART) is largely based on CD4+ T cell counts and viral load, measures that fail to take into account the CD8+ T cell subset, known to show features of accelerated aging in HIV disease. Here, we compare adenosine deaminase (ADA), glucose uptake receptor 1 (GLUT1), and leucine-rich repeat neuronal 3 (LRRN3) to CD38 expression and telomerase activity, two strong predictors of HIV disease progression. Our analysis revealed that reduced ADA, telomerase activity and LRRN3 gene expression were significantly associated with high CD38 and HLA-DR in CD8+ T cells, with % ADA+ cells being the most robust predictor of CD8+ T cell activation. Our results suggest that ADA, LRRN3 and telomerase activity in CD8+ T cells may serve as novel, clinically relevant biomarkers of immune status in HIV-1 infection, specifically by demonstrating the degree to which CD8+ T cells have progressed to the end stage of replicative senescence. Since chronological aging itself leads to the accumulation of senescent CD8+ T cells, the prolonged survival and resultant increased age of the HIV+ population may synergize with the chronic immune activation to exacerbate both immune decline and age-associated pathologies. The identification and future validation of these new biomarkers may lead to fresh immune-based HIV treatments.

T cell replicative senescence in human aging.

The decline of the immune system appears to be an intractable consequence of aging, leading to increased susceptibility to infections, reduced effectiveness of vaccination and higher incidences of many diseases including osteoporosis and cancer in the elderly. These outcomes can be attributed, at least in part, to a phenomenon known as T cell replicative senescence, a terminal state characterized by dysregulated immune function, loss of the CD28 costimulatory molecule, shortened telomeres and elevated production of proinflammatory cytokines. Senescent CD8 T cells, which accumulate in the elderly, have been shown to frequently bear antigen specificity against cytomegalovirus (CMV), suggesting that this common and persistent infection may drive immune senescence and result in functional and phenotypic changes to the T cell repertoire. Senescent T cells have also been identified in patients with certain cancers, autoimmune diseases and chronic infections, such as HIV. This review discusses the in vivo and in vitro evidence for the contribution of CD8 T cell replicative senescence to a plethora of age-related pathologies and a few possible therapeutic avenues to delay or prevent this differentiative end-state in T cells. The age-associated remodeling of the immune system, through accumulation of senescent T cells has farreaching consequences on the individual and society alike, for the current healthcare system needs to meet the urgent demands of the increasing proportions of the elderly in the US and abroad.

Male choice in the stream-anadromous stickleback complex.

Studies of mating preferences and pre-mating reproductive isolation have often focused on females, but the potential importance of male preferences is increasingly appreciated. We investigated male behavior in the context of reproductive isolation between divergent anadromous and stream-resident populations of threespine stickleback, Gasterosteus aculeatus, using size-manipulated females of both ecotypes. Specifically, we asked if male courtship preferences are present, and if they are based on relative body size, non-size aspects of ecotype, or other traits. Because male behaviors were correlated with each other, we conducted a principal components analysis on the correlations and ran subsequent analyses on the principal components. The two male ecotypes differed in overall behavioral frequencies, with stream-resident males exhibiting consistently more vigorous and positive courtship than anadromous males, and an otherwise aggressive behavior playing a more positive role in anadromous than stream-resident courtship. We observed more vigorous courtship toward smaller females by (relatively small) stream-resident males and the reverse pattern for (relatively large) anadromous males. Thus size-assortative male courtship preferences may contribute to reproductive isolation in this system, although preferences are far from absolute. We found little indication of males responding preferentially to females of their own ecotype independent of body size.

Evidence for ecology's role in speciation.

A principal challenge in testing the role of natural selection in speciation is to connect the build-up of reproductive isolation between populations to divergence of ecologically important traits. Demonstrations of 'parallel speciation', or assortative mating by selective environment, link ecology and isolation, but the phenotypic traits mediating isolation have not been confirmed. Here we show that the parallel build-up of mating incompatibilities between stickleback populations can be largely accounted for by assortative mating based on one trait, body size, which evolves predictably according to environment. In addition to documenting the influence of body size on reproductive isolation for stickleback populations spread across the Northern Hemisphere, we have confirmed its importance through a new experimental manipulation. Together, these results suggest that speciation may arise largely as a by-product of ecological differences and divergent selection on a small number of phenotypic traits.

Modified isocratic capillary electrophoresis detection of cell-free DNA in semen.

PURPOSE: The objectives were: i) to analyze semen for the presence of cell-free DNA and ii) to determine the association between sperm parameters and cell-free DNA. METHODS: Cell-free DNA in semen (N = 25 cases) were detected using the modified capillary gel electrophoresis (CE) procedure. SYBR-Gold was used to stain high (12 Kb) and low (1 Kb) molecular weight DNA fragments and the images analyzed. RESULTS: The quantity of low-molecular weight cell-free DNA was positively correlated to rapid progression, curvilinear velocity (>40 microm/s), normal strict morphology and capacitation index. High-molecular weight cell-free DNA intensity index was negatively correlated to post-wash hyperactivation. Sperm concentration was not related to cell-free DNA quantity. The sperm freezing process did not increase cell-free DNA but reduced the more labile low-molecular weight cell-free DNA. CONCLUSIONS: Cell-free DNA present in semen was correlated to important sperm parameters linked to normal sperm function. The data suggested the possible use of cell-free DNA as a marker of semen quality. This study reports on the novel finding of cell-free DNA released along with sperm during each ejaculation.