A hybrid open-top light-sheet microscope for versatile multi-scale imaging of cleared tissues.

Light-sheet microscopy has emerged as the preferred means for high-throughput volumetric imaging of cleared tissues. However, there is a need for a flexible system that can address imaging applications with varied requirements in terms of resolution, sample size, tissue-clearing protocol, and transparent sample-holder material. Here, we present a 'hybrid' system that combines a unique non-orthogonal dual-objective and conventional (orthogonal) open-top light-sheet (OTLS) architecture for versatile multi-scale volumetric imaging. We demonstrate efficient screening and targeted sub-micrometer imaging of sparse axons within an intact, cleared mouse brain. The same system enables high-throughput automated imaging of multiple specimens, as spotlighted by a quantitative multi-scale analysis of brain metastases. Compared with existing academic and commercial light-sheet microscopy systems, our hybrid OTLS system provides a unique combination of versatility and performance necessary to satisfy the diverse requirements of a growing number of cleared-tissue imaging applications.

Adult spinal deformity surgery: a systematic review of venous thromboprophylaxis and incidence of venous thromboembolic events.

Venous thromboprophylaxis consisting of chemical and/or mechanical prophylaxis is administered to patients undergoing adult spinal deformity (ASD) surgery to prevent venous thromboembolic events. However, the true incidence of venous thromboembolism (VTE) after these surgeries is unknown resulting in weak recommendations and lack of consensus regarding type and timing of prophylaxis in these patients. A systematic literature review was conducted to examine VTE incidence in addition to optimal type and timing of VTE prophylaxis. A detailed search was carried out on Embase, PubMed, and Cochrane Library databases through October 18, 2017, for studies that evaluated venous thromboembolic outcomes, type, and timing of prophylaxis administration among ASD surgery patients who were on VTE prophylaxis. The randomized study was assessed for risk of bias using the Cochrane tool and the observational studies using the Newcastle-Ottawa scale (NOS). The search yielded 1180 studies, and three articles published between 1996 and 2008 met the inclusion criteria. There were 583 surgeries performed on 537 patients with a mean age ranging from 45 to 52 years. Females dominated the study with percentages ranging from 60 to 94% in the different study populations. VTE prophylaxis was initiated before surgery in 87.7% patients and intraoperatively in 12.3% patients. VTE incidence ranged between 0 and 9.1% among the studies. VTE can occur after ASD surgery regardless of the type of prophylaxis, and incidence may be higher when mechanical prophylaxis alone is initiated intraoperatively. Further studies to examine VTE prophylaxis in patients undergoing ASD surgery should be considered.

Redirecting adult mesenchymal stromal cells to the brain: a new approach for treating CNS autoimmunity and neuroinflammation?

Mesenchymal stromal cells or stem cells (MSCs) have been shown to participate in tissue repair and are immunomodulatory in neuropathological settings. Given this, their potential use in developing a new generation of personalized therapies for autoimmune and inflammatory diseases of the central nervous system (CNS) will be explored. To effectively exert these effector functions, MSCs must first gain entry into damaged neural tissues, a process that has been demonstrated to be a limiting factor in their therapeutic efficacy. In this review, we discuss approaches to maximize the therapeutic efficacy of MSCs by altering their intrinsic trafficking programs to effectively enter neuropathological sites. To this end, we explore the significant role of chemokine receptors and adhesion molecules in directing cellular traffic to the inflamed CNS and the capacity of MSCs to adopt these molecular mechanisms to gain entry to this site. We postulate that understanding and exploiting these migratory mechanisms may be key to the development of cell-based therapies tailored to respond to the migratory cues unique to the nature and stage of progression of individual CNS disorders.

A disrupted FOXP3 transcriptional signature underpins systemic regulatory T cell insufficiency in early pregnancy failure.

Regulatory T (Treg) cell defects are implicated in disorders of embryo implantation and placental development, but the origins of Treg cell dysfunction are unknown. Here, we comprehensively analyzed the phenotypes and transcriptional profile of peripheral blood Treg cells in individuals with early pregnancy failure (EPF). Compared to fertile subjects, EPF subjects had 32% fewer total Treg cells and 54% fewer CD45RA+CCR7+ naive Treg cells among CD4+ T cells, an altered Treg cell phenotype with reduced transcription factor FOXP3 and suppressive marker CTLA4 expression, and lower Treg:Th1 and Treg:Th17 ratios. RNA sequencing demonstrated an aberrant gene expression profile, with upregulation of pro-inflammatory genes including CSF2, IL4, IL17A, IL21, and IFNG in EPF Treg cells. In silico analysis revealed 25% of the Treg cell dysregulated genes are targets of FOXP3. We conclude that EPF is associated with systemic Treg cell defects arising due to disrupted FOXP3 transcriptional control and loss of lineage fidelity.

Inhibition of antiapoptotic BCL-2 proteins with ABT-263 induces fibroblast apoptosis, reversing persistent pulmonary fibrosis.

Patients with progressive fibrosing interstitial lung diseases (PF-ILDs) carry a poor prognosis and have limited therapeutic options. A hallmark feature is fibroblast resistance to apoptosis, leading to their persistence, accumulation, and excessive deposition of extracellular matrix. A complex balance of the B cell lymphoma 2 (BCL-2) protein family controlling the intrinsic pathway of apoptosis and fibroblast reliance on antiapoptotic proteins has been hypothesized to contribute to this resistant phenotype. Examination of lung tissue from patients with PF-ILD (idiopathic pulmonary fibrosis and silicosis) and mice with PF-ILD (repetitive bleomycin and silicosis) showed increased expression of antiapoptotic BCL-2 family members in α-smooth muscle actin-positive fibroblasts, suggesting that fibroblasts from fibrotic lungs may exhibit increased susceptibility to inhibition of antiapoptotic BCL-2 family members BCL-2, BCL-XL, and BCL-W with the BH3 mimetic ABT-263. We used 2 murine models of PF-ILD to test the efficacy of ABT-263 in reversing established persistent pulmonary fibrosis. Treatment with ABT-263 induced fibroblast apoptosis, decreased fibroblast numbers, and reduced lung collagen levels, radiographic disease, and histologically evident fibrosis. Our studies provide insight into how fibroblasts gain resistance to apoptosis and become sensitive to the therapeutic inhibition of antiapoptotic proteins. By targeting profibrotic fibroblasts, ABT-263 offers a promising therapeutic option for PF-ILDs.

Regulation of epithelial transitional states in murine and human pulmonary fibrosis.

Idiopathic pulmonary fibrosis (IPF) is a progressive scarring disease arising from impaired regeneration of the alveolar epithelium after injury. During regeneration, type 2 alveolar epithelial cells (AEC2s) assume a transitional state that upregulates multiple keratins and ultimately differentiate into AEC1s. In IPF, transitional AECs accumulate with ineffectual AEC1 differentiation. However, whether and how transitional cells cause fibrosis, whether keratins regulate transitional cell accumulation and fibrosis, and why transitional AECs and fibrosis resolve in mouse models but accumulate in IPF are unclear. Here, we show that human keratin 8 (KRT8) genetic variants were associated with IPF. Krt8-/- mice were protected from fibrosis and accumulation of the transitional state. Keratin 8 (K8) regulated the expression of macrophage chemokines and macrophage recruitment. Profibrotic macrophages and myofibroblasts promoted the accumulation of transitional AECs, establishing a K8-dependent positive feedback loop driving fibrogenesis. Finally, rare murine transitional AECs were highly senescent and basaloid and may not differentiate into AEC1s, recapitulating the aberrant basaloid state in human IPF. We conclude that transitional AECs induced and were maintained by fibrosis in a K8-dependent manner; in mice, most transitional cells and fibrosis resolved, whereas in human IPF, transitional AECs evolved into an aberrant basaloid state that persisted with progressive fibrosis.

Regulatory T Cell Proportion and Phenotype Are Altered in Women Using Oral Contraception.

Regulatory T (Treg) cells are a specialized CD4+ T cell subpopulation that are essential for immune homeostasis, immune tolerance, and protection against autoimmunity. There is evidence that sex-steroid hormones estrogen and progesterone modulate Treg cell abundance and phenotype in women. Since natural oscillations in these hormones are modified by hormonal contraceptives, we examined whether oral contraception (OC) use impacts Treg cells and related T cell populations. T cells were analyzed by multiparameter flow cytometry in peripheral blood collected across the menstrual cycle from healthy women either using OC or without hormonal contraception and from age-matched men. Compared to naturally cycling women, women using OC had fewer Treg cells and an altered Treg cell phenotype. Notably, Treg cells exhibiting a strongly suppressive phenotype, defined by high FOXP3, CD25, Helios, HLADR, CTLA4, and Ki67, comprised a lower proportion of total Treg cells, particularly in the early- and mid-cycle phases. The changes were moderate compared to more substantial differences in Treg cells between women and men, wherein women had fewer Treg cells-especially of the effector memory Treg cell subset-associated with more T helper type 1 (Th1) cells and CD8+ T cells and lower Treg:Th1 cell and Treg:CD8+ T cell ratios than men. These findings imply that OC can modulate the number and phenotype of peripheral blood Treg cells and raise the possibility that Treg cells contribute to the physiological changes and altered disease susceptibility linked with OC use.

Effect of Intralipid infusion on peripheral blood T cells and plasma cytokines in women undergoing assisted reproduction treatment.

OBJECTIVES: Intravenous infusion of Intralipid is an adjunct therapy in assisted reproduction treatment (ART) when immune-associated infertility is suspected. Here, we evaluated the effect of Intralipid infusion on regulatory T cells (Treg cells), effector T cells and plasma cytokines in peripheral blood of women undertaking IVF. METHODS: This prospective, observational pilot study assessed Intralipid infusion in 14 women exhibiting recurrent implantation failure, a clinical sign of immune-associated infertility. Peripheral blood was collected immediately prior to and 7 days after intravenous administration of Intralipid. Plasma cytokines were measured by Luminex, and T-cell subsets were analysed by flow cytometry. RESULTS: A small increase in conventional CD8+ T cells occurred after Intralipid infusion, but no change was seen in CD4+ Treg cells, or naïve, memory or effector memory T cells. Proliferation marker Ki67, transcription factors Tbet and RORγt, and markers of suppressive capacity CTLA4 and HLA-DR were unchanged. Dimensionality-reduction analysis using the tSNE algorithm confirmed no phenotype shift within Treg cells or other T cells. Intralipid infusion increased plasma CCL2, CCL3, CXCL8, GM-CSF, G-CSF, IL-6, IL-21, TNF and VEGF. CONCLUSION: Intralipid infusion elicited elevated pro-inflammatory cytokines, and a minor increase in CD8+ T cells, but no change in pro-tolerogenic Treg cells. Notwithstanding the limitation of no placebo control, the results do not support Intralipid as a candidate intervention to attenuate the Treg cell response in women undergoing ART. Future placebo-controlled studies are needed to confirm the potential efficacy and clinical significance of Intralipid in attenuating cytokine induction and circulating CD8+ T cells.

Direct interaction of whole-inactivated influenza A and pneumococcal vaccines enhances influenza-specific immunity.

The upper respiratory tract is continuously exposed to a vast array of potentially pathogenic viruses and bacteria. Influenza A virus (IAV) has particular synergism with the commensal bacterium Streptococcus pneumoniae in this niche, and co-infection exacerbates pathogenicity and causes significant mortality. However, it is not known whether this synergism is associated with a direct interaction between the two pathogens. We have previously reported that co-administration of a whole-inactivated IAV vaccine (γ-Flu) with a whole-inactivated pneumococcal vaccine (γ-PN) enhances pneumococcal-specific responses. In this study, we show that mucosal co-administration of γ-Flu and γ-PN similarly augments IAV-specific immunity, particularly tissue-resident memory cell responses in the lung. In addition, our in vitro analysis revealed that S. pneumoniae directly interacts with both γ-Flu and with live IAV, facilitating increased uptake by macrophages as well as increased infection of epithelial cells by IAV. These observations provide an additional explanation for the synergistic pathogenicity of IAV and S. pneumoniae, as well as heralding the prospect of exploiting the phenomenon to develop better vaccine strategies for both pathogens.

Characterization of tear production in subjects with dry eye disease during intranasal tear neurostimulation: Results from two pivotal clinical trials.

PURPOSE: The intranasal tear neurostimulator (ITN) activates the nasolacrimal pathway, which is involved with basal and bolus tear secretion. These studies characterized the acute and long-term effectiveness of the ITN in stimulating tear production in subjects with dry eye disease (DED). METHODS: Study 1: Randomized, double-masked, dual-controlled, 1-day crossover. Study 2: Single-arm, open-label, 180-day prospective cohort. Eligible subjects had basal unstimulated Schirmer test (with anesthesia) ≤10 mm and intranasal cotton swab-stimulated Schirmer test at least 7 mm greater in the same eye, and Ocular Surface Disease Index® ≥13 and ≥ 23, in Studies 1 and 2, respectively. Study 1: Subjects (n = 48) received three randomized test applications: active intranasal, extranasal (active control), and sham intranasal (inactive control) stimulation, 3 min/application with 1-hour minimum between applications. Primary outcome measure was the difference in Schirmer test scores during active intranasal and control applications. Study 2: Subjects (n = 97) performed intranasal neurostimulation for ≤3 min/application, 2-10 times/day. Primary outcome measure was the difference in Schirmer scores (stimulated minus unstimulated) at day 180. Both studies recorded device-related adverse events (AEs). RESULTS: Study 1: Schirmer scores (mean ±â€¯SEM) were significantly greater (p < 0.0001) with active intranasal (25.3 ±â€¯1.5 mm) vs extranasal (9.5 ±â€¯1.2 mm) and sham (9.2 ±â€¯1.1 mm) applications. Study 2: Schirmer scores were significantly greater (p < 0.0001) with ITN stimulation vs unstimulated at day 180 (17.3 ±â€¯1.3 mm vs 7.9 ±â€¯0.7 mm). No serious device-related AEs were reported in either study. CONCLUSION: The ITN was well-tolerated and effective in stimulating tear production with acute and long-term use in DED. CLINICALTRIALS. GOV IDENTIFIER: NCT02680158 and NCT02526290.

IL-17-producing γδ T cells switch migratory patterns between resting and activated states.

Interleukin 17-producing γδ T (γδT17) cells have unconventional trafficking characteristics, residing in mucocutaneous tissues but also homing into inflamed tissues via circulation. Despite being fundamental to γδT17-driven early protective immunity and exacerbation of autoimmunity and cancer, migratory cues controlling γδT17 cell positioning in barrier tissues and recruitment to inflammatory sites are still unclear. Here we show that γδT17 cells constitutively express chemokine receptors CCR6 and CCR2. While CCR6 recruits resting γδT17 cells to the dermis, CCR2 drives rapid γδT17 cell recruitment to inflamed tissues during autoimmunity, cancer and infection. Downregulation of CCR6 by IRF4 and BATF upon γδT17 activation is required for optimal recruitment of γδT17 cells to inflamed tissue by preventing their sequestration into uninflamed dermis. These findings establish a lymphocyte trafficking model whereby a hierarchy of homing signals is prioritized by dynamic receptor expression to drive both tissue surveillance and rapid recruitment of γδT17 cells to inflammatory lesions.