Sequential liver and haematopoietic stem cell transplantation in a case of fulminant hepatitis associated liver failure and aplastic anaemia

The management of severe aplastic anaemia is particularly challenging when it occurs in the context of recent liver transplantation. Rapid identification of a suitable donor followed by allogeneic haematopoietic stem cell transplantation is the only curative option. This scenario is often complicated by potentially life‐threatening infections that develop as a consequence of immunosuppression. Alternative donor transplantation using suitably matched unrelated donors can be potentially life‐saving when suitably matched sibling donors are unavailable. Above all, a dedicated interdisciplinary approach with seamless communication between hepatology, transplant surgery, haematology, and stem cell transplant services is essential to achieving optimal outcomes. Herein, we describe a case of severe hepatitis leading to hepatic failure who was treated with liver transplantation from a deceased donor, and later received an allogeneic haematopoietic stem cell transplantation from a matched unrelated donor for hepatitis‐associated aplastic anaemia.     

Infrarenal abdominal aortic aneurysms

Opinion statement Screening programs should be instituted to identify patients with small asymptomatic abdominal aortic aneurysms (AAAs) in the community. Screening for AAAs reduces the rate of aneurysm rupture and reduces death from aneurysmal disease in the population. The indications for aneurysm surgery have been defined by two recent randomized clinical trials. Patients with symptomatic or ruptured AAAs should be treated by urgent or emergency surgery. Patients with asymptomatic AAAs should not undergo surgical repair until the aneurysm exceeds 5.4 cm in maximum diameter. The most appropriate surgical option for the majority of patients with AAAs is conventional inlay grafting. This may be approached transperitoneally, although the retroperitoneal approach is favored for inflammatory or juxtarenal aneurysms. Conventional aneurysm repair may be performed with acceptable mortality and good long-term durability in specialized centers with a high volume of cases. The place of endovascular aneurysm repair remains to be defined. Endovascular repair is the best option in high-risk patients with suitable aneurysm morphology. The questions over the long-term durability of endovascular aneurysm surgery in preventing aneurysm rupture make it unsuitable for young patients. Randomized trials will define the indications for this technique. Endovascular surgery is likely to become the most appropriate treatment for ruptured aneurysms in the next decade.     

Age matters: differences in correlates of self-reported HIV antiretroviral treatment adherence between older and younger Black men who have sex with men living with HIV

Black men who have sex with men (BMSM) show lower levels of adherence to antiretroviral therapy (ART) for HIV medications than other racial/ethnic groups in the U.S. Yet, little is known about age differences in factors that predict ART adherence among BMSM. We combined data from two surveys of HIV-positive BMSM, resulting in 209 participants (130 aged 18–50 years; 79 aged 50 years or older). Multivariate linear regressions examined associations between baseline characteristics and adherence to HIV medications as well as interactions of baseline characteristics with age. The associations between trust in healthcare and doctor satisfaction ratings with higher adherence were stronger for older vs younger men (p?<?.05); the association between problem drinking and lower adherence was stronger among younger men (p?<?.05). Future research should examine how interventions may address these age-specific factors to improve ART adherence among BMSM living with HIV.     

Circulating 25-hydroxyvitamin D is associated with insulin resistance cross-sectionally but not longitudinally in older adults: The Cardiovascular Health Study

BackgroundDespite extensive study, the role of vitamin D in insulin resistance and secretion remains unclear.ObjectiveTo examine the cross-sectional and longitudinal relationships between 25-hydroxyvitamin D (25(OH)D) concentrations and indices of insulin resistance and secretion in older adults.Methods and ResultsAmong 2134 participants of the Cardiovascular Health Study who were free from cardiovascular disease, we measured serum 25(OH)D concentrations in samples collected in 1992–1993. We examined insulin resistance and secretion using Homeostasis Model Assessment (HOMA) estimates cross-sectionally and among 1469 participants who had repeated HOMA measures four years later (1996–1997). In cross-sectional analysis, each 10 ng/mL increment in 25(OH)D concentration was associated with a 0.09 lower adjusted HOMA-IR [95% CI (? 0.17, ? 0.02), p = 0.01]. However, baseline 25(OH)D concentrations were not associated with change in HOMA-IR over 4 years of follow up (p = 0.48). 25(OH)D concentrations were not associated with insulin secretion, as determined by HOMA-β, in either cross-sectional or longitudinal analysis.ConclusionsCirculating 25(OH)D concentrations are associated with lower insulin resistance in cross-sectional but not longitudinal analyses. Whether this reflects residual confounding in cross-sectional analyses or the short-term nature of the relationship between vitamin D and insulin sensitivity will require trials with repeated measures of these factors.     

Self-organization of bacterial biofilms is facilitated by extracellular DNA

Twitching motility-mediated biofilm expansion is a complex, multicellular behavior that enables the active colonization of surfaces by many species of bacteria. In this study we have explored the emergence of intricate network patterns of interconnected trails that form in actively expanding biofilms of Pseudomonas aeruginosa. We have used high-resolution, phase-contrast time-lapse microscopy and developed sophisticated computer vision algorithms to track and analyze individual cell movements during expansion of P. aeruginosa biofilms. We have also used atomic force microscopy to examine the topography of the substrate underneath the expanding biofilm. Our analyses reveal that at the leading edge of the biofilm, highly coherent groups of bacteria migrate across the surface of the semisolid media and in doing so create furrows along which following cells preferentially migrate. This leads to the emergence of a network of trails that guide mass transit toward the leading edges of the biofilm. We have also determined that extracellular DNA (eDNA) facilitates efficient traffic flow throughout the furrow network by maintaining coherent cell alignments, thereby avoiding traffic jams and ensuring an efficient supply of cells to the migrating front. Our analyses reveal that eDNA also coordinates the movements of cells in the leading edge vanguard rafts and is required for the assembly of cells into the “bulldozer” aggregates that forge the interconnecting furrows. Our observations have revealed that large-scale self-organization of cells in actively expanding biofilms of P. aeruginosa occurs through construction of an intricate network of furrows that is facilitated by eDNA.     

Development and validation of a single‐cell network profiling assay‐based classifier to predict response to induction therapy in paediatric patients with de novo acute myeloid leukaemia: a report from the Children's Oncology Group

Single cell network profiling (SCNP) is a multi‐parameter flow cytometry technique for simultaneous interrogation of intracellular signalling pathways. Diagnostic paediatric acute myeloid leukaemia (AML) bone marrow samples were used to develop a classifier for response to induction therapy in 53 samples and validated in an independent set of 68 samples. The area under the curve of a receiver operating characteristic curve (AUC_ROC) was calculated to be 0·85 in the training set and after exclusion of induction deaths, the AUC_ROC of the classifier was 0·70 (P = 0·02) and 0·67 (P = 0·04) in the validation set when induction deaths (intent to treat) were included. The highest predictive accuracy was noted in the cytogenetic intermediate risk patients (AUC_ROC 0·88, P = 0·002), a subgroup that lacks prognostic/predictive biomarkers for induction response. Only white blood cell count and cytogenetic risk were associated with response to induction therapy in the validation set. After controlling for these variables, the SCNP classifier score was associated with complete remission (P = 0·017), indicating that the classifier provides information independent of other clinical variables that were jointly associated with response. This is the first validation of an SCNP classifier to predict response to induction chemotherapy. Herein we demonstrate the usefulness of quantitative SCNP under modulated conditions to provide independent information on AML disease biology and induction response.     

Impact of allogeneic hematopoietic cell transplant in patients with myeloid neoplasms carrying spliceosomal mutations

Molecular predictors of outcome are increasingly important in determining optimal therapy for myeloid neoplasms. Mutations in the spliceosomal genes (U2AF1 and SRSF2) predict for poor outcomes in myelodysplastic syndromes (MDS) and related diseases. We investigated the effect of hematopoietic cell transplant (HCT) on the negative prognostic impact of U2AF1 and SRSF2 mutations. In total, 122 patients with MDS (30%), acute myeloid leukemia (51%), myeloproliferative neoplasms (MPN) (11%), and MDS/MPN (8%) receiving a HCT from 2003 to 2012 were evaluated for mutations in U2AF1 and SRSF2 by direct sequencing. Median time of follow up was 24 months (range 0.46–110). SRSF2 mutations were detected in 11 (10%) patients and U2AF1 in 3 (3%) patients. There were no significant differences in baseline characteristics between mutated and wild‐type (WT) patients. Patients carrying SRSF2 and U2AF1 mutations had similar overall survival (P = 0.84), relapse mortality (P = 0.50), and non‐relapse mortality (P = 0.72) compared to WT patients. However, taking into account disease status and cytogenetics in a subset of AML patients, SRSF2 and U2AF1 mutations were associated with worse survival (HR 3.71, P = 0.035). Am. J. Hematol. 91:406–409, 2016. © 2016 Wiley Periodicals, Inc.     

Do People Know I’m Poz?: Factors Associated with Knowledge of Serostatus Among HIV-Positive African Americans’ Social Network Members

We examined how functional social support, HIV-related discrimination, internalized HIV stigma, and social network structure and composition were cross-sectionally associated with network members’ knowledge of respondents’ serostatus among 244 HIV-positive African Americans in Los Angeles. Results of a generalized hierarchical linear model indicated people in respondents’ networks who were highly trusted, well-known to others (high degree centrality), HIV-positive, or sex partners were more likely to know respondents’ HIV serostatus; African American network members were less likely to know respondents’ serostatus, as were drug-using partners. Greater internalized stigma among respondents living with HIV was associated with less knowledge of their seropositivity within their social network whereas greater respondent-level HIV discrimination was associated with more knowledge of seropositivity within the network. Additional research is needed to understand the causal mechanisms and mediating processes associated with serostatus disclosure as well as the long-term consequences of disclosure and network members’ knowledge of respondents’ serostatus.     

Individual-Level,Partnership-Level,and Sexual Event-Level Predictors of Condom Use During Receptive Anal Intercourse Among HIV-Negative Men Who Have Sex with Men in Los Angeles

We examined individual-level, partnership-level, and sexual event-level factors associated with condom use during receptive anal intercourse (RAI) among 163 low-income, racially/ethnically diverse, HIV-negative men who have sex with men (MSM) in Los Angeles (2007–2010). At baseline, 3-month, and 12-month visits, computer-assisted self-interviews collected information on ≤3 recent male partners and the last sexual event with those partners. Factors associated with condom use during RAI at the last sexual event were identified using logistic generalized linear mixed models. Condom use during RAI was negatively associated with reporting ≥ high school education (adjusted odds ratio [AOR] = 0.32, 95 % confidence interval [CI] 0.11–0.96) and methamphetamine use, specifically during RAI events with non-main partners (AOR = 0.20, 95 % CI 0.07–0.53) and those that included lubricant use (AOR = 0.20, 95 % CI 0.08–0.53). Condom use during RAI varies according to individual-level, partnership-level, and sexual event-level factors that should be considered in the development of risk reduction strategies for this population.     

INAUGURAL ARTICLE by a Recently Elected Academy Member:Contractility,focal adhesion orientation,and stress fiber orientation drive cancer cell polarity and migration along wavy ECM substrates

Contact guidance is a powerful topographical cue that induces persistent directional cell migration. Healthy tissue stroma is characterized by a meshwork of wavy extracellular matrix (ECM) fiber bundles, whereas metastasis-prone stroma exhibit less wavy, more linear fibers. The latter topography correlates with poor prognosis, whereas more wavy bundles correlate with benign tumors. We designed nanotopographic ECM-coated substrates that mimic collagen fibril waveforms seen in tumors and healthy tissues to determine how these nanotopographies may regulate cancer cell polarization and migration machineries. Cell polarization and directional migration were inhibited by fibril-like wave substrates above a threshold amplitude. Although polarity signals and actin nucleation factors were required for polarization and migration on low-amplitude wave substrates, they did not localize to cell leading edges. Instead, these factors localized to wave peaks, creating multiple “cryptic leading edges” within cells. On high-amplitude wave substrates, retrograde flow from large cryptic leading edges depolarized stress fibers and focal adhesions and inhibited cell migration. On low-amplitude wave substrates, actomyosin contractility overrode the small cryptic leading edges and drove stress fiber and focal adhesion orientation along the wave axis to mediate directional migration. Cancer cells of different intrinsic contractility depolarized at different wave amplitudes, and cell polarization response to wavy substrates could be tuned by manipulating contractility. We propose that ECM fibril waveforms with sufficiently high amplitude around tumors may serve as “cell polarization barriers,” decreasing directional migration of tumor cells, which could be overcome by up-regulation of tumor cell contractility.

One hallmark of tumor progression to more advanced stages and worsening patient prognosis is the remodeling of the extracellular matrix (ECM) in the tumor microenvironment by fibroblasts (1) and macrophages (2). In several tumor types—including breast (3, 4), skin (5), ovary (6, 7), colon (2), and liver (8)—such remodeling is characterized by stiffening and reorganization of normally wavy stromal collagen bundles into thick linear bundles. Linear bundles are thought to provide “tracks” to mediate metastatic cell migration out of the primary tumor, whereas curved or wavy bundles typical of normal stroma are thought to inhibit cell movement (9, 10). The notion that linear ECM fibers support tumor metastasis arose from the longstanding observation that cells of many types polarize and migrate directionally in response to anisotropic physical cues, such as linear fibrils or grooves in a substrate, in a process called contact guidance (11). In support of this, ovarian cancer cells migrate more actively on ECM substrates that mimic the collagen architecture of aggressive ovarian tumors than on those mimicking normal or benign stroma (12). It is thought that the effects of comorbidities on ECM architecture, for example obesity in which breast stroma exhibits more linear collagen bundles than seen in lean tissue, may predispose patients to worse clinical outcomes when cancer does arise (13). However, a direct link between metastasis and the migratory behavior of cancer cells in response to linear or wavy or ECM fibril architecture has not been established, and the mechanisms by which such regulation might occur are unknown.Cell polarization and migration in response to anisotropic cues during contact guidance, chemotaxis, haptotaxis, or durotaxis is mediated by similar molecular mechanisms. Polarization is initiated by ligand binding by growth factor or ECM receptors that promote Rho GTPases (14, 15), and is enforced by spatial segregation of phosphatidylinositol 3-kinase (PI3K) at the leading edge to produce phosphatidylinositol-3,4,5-triphosphate (PIP3) and the phosphatase and tensin homolog (PTEN) removing PIP3 at the cell rear (16–18). PIP3 and Rho GTPases at the leading edge promote polarization of the microtubule cytoskeleton and Golgi apparatus, as well as actin polymerization via Arp2/3 and formins (19–23), to drive leading-edge protrusions. Retrograde flow of the polymerizing actin network at the leading edge is coupled to integrin-based focal adhesions (FAs) via a molecular clutch (24, 25), which engages FAs to the ECM. Recruitment of myosin II to the polymerizing actin contracts the network, creating actin arcs and stress fibers in the lamella, maturing the FAs and orienting them in the direction of cell migration (26–30). Disassembly of FAs toward the rear of the cell allows forward movement (31–35). Artificial enforcement of this organization of actin polymerization and adhesions by micropatterned ECMs alone is sufficient to define the polarity of the cell, independent of other stimuli (36). However, how these molecular mechanisms are modulated by the differing stromal collagen architectures associated with normal or tumor tissue is not known.Here we sought to examine the contact-guidance–mediated polarization and migration responses of tumor cells to ECM fibril architectures mimicking those seen in normal and tumor stroma, and to dissect the mechanisms of these responses. We designed synthetic nanotopographic ECM-coated substrates that approximate collagen fibril size and the range of waveforms observed in tumors and tissues from mouse and human samples, and we determined their effect on the organization and dynamics of the cell polarity and migration machineries. We find that cell polarization and directional migration are inhibited by sinusoidal fibril-like waves above a threshold amplitude by geometrically constrained effects on the organization of actomyosin contractility and FA orientation. Importantly, we found that cancer cells of different intrinsic contractility depolarized at different ECM-wave amplitudes, and that cell polarization could be tuned on wavy substrates by manipulating contractility. Thus, the ECM-fibril waveform, in addition to other factors in the tumor microenvironment, may regulate cancer cells’ ability to migrate out of tumors, and their contractility level may dictate the range of ECM architectures that allow migration.