There is a clinical need for noninvasive biomarkers of tumor hypoxia for prognostic and predictive studies, radiotherapy planning, and therapy monitoring. Oxygen-enhanced MRI (OE-MRI) is an emerging ...imaging technique for quantifying the spatial distribution and extent of tumor oxygen delivery in vivo. In OE-MRI, the longitudinal relaxation rate of protons (ΔR1) changes in proportion to the concentration of molecular oxygen dissolved in plasma or interstitial tissue fluid. Therefore, well-oxygenated tissues show positive ΔR1. We hypothesized that the fraction of tumor tissue refractory to oxygen challenge (lack of positive ΔR1, termed "Oxy-R fraction") would be a robust biomarker of hypoxia in models with varying vascular and hypoxic features. Here, we demonstrate that OE-MRI signals are accurate, precise, and sensitive to changes in tumor pO2 in highly vascular 786-0 renal cancer xenografts. Furthermore, we show that Oxy-R fraction can quantify the hypoxic fraction in multiple models with differing hypoxic and vascular phenotypes, when used in combination with measurements of tumor perfusion. Finally, Oxy-R fraction can detect dynamic changes in hypoxia induced by the vasomodulator agent hydralazine. In contrast, more conventional biomarkers of hypoxia (derived from blood oxygenation-level dependent MRI and dynamic contrast-enhanced MRI) did not relate to tumor hypoxia consistently. Our results show that the Oxy-R fraction accurately quantifies tumor hypoxia noninvasively and is immediately translatable to the clinic.
Antiangiogenic therapy is efficacious in metastatic renal cell carcinoma (mRCC). However, the ability of antiangiogenic drugs to delay tumor progression and extend survival is limited, due to either ...innate or acquired drug resistance. Furthermore, there are currently no validated biomarkers that predict which mRCC patients will benefit from antiangiogenic therapy. Here, we exploit susceptibility contrast MRI (SC-MRI) using intravascular ultrasmall superparamagnetic iron oxide particles to quantify and evaluate tumor fractional blood volume (fBV) as a noninvasive imaging biomarker of response to the antiangiogenic drug sunitinib. We also interrogate the vascular phenotype of RCC xenografts exhibiting acquired resistance to sunitinib. SC-MRI of 786-0 xenografts prior to and 2 weeks after daily treatment with 40 mg/kg sunitinib revealed a 71% (
< 0.01) reduction in fBV in the absence of any change in tumor volume. This response was associated with significantly lower microvessel density (
< 0.01) and lower uptake of the perfusion marker Hoechst 33342 (
< 0.05). The average pretreatment tumor fBV was negatively correlated (
= 0.92,
< 0.0001) with sunitinib-induced changes in tumor fBV across the cohort. SC-MRI also revealed suppressed fBV in tumors that acquired resistance to sunitinib. In conclusion, SC-MRI enabled monitoring of the antiangiogenic response of 786-0 RCC xenografts to sunitinib, which revealed that pretreatment tumor fBV was found to be a predictive biomarker of subsequent reduction in tumor blood volume in response to sunitinib, and acquired resistance to sunitinib was not associated with a parallel increase in tumor blood volume.
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The liver is bathed in bacterial products, including lipopolysaccharide transported from the intestinal portal vasculature, but maintains a state of tolerance that is exploited by persistent ...pathogens and tumours
. The cellular basis mediating this tolerance, yet allowing a switch to immunity or immunopathology, needs to be better understood for successful immunotherapy of liver diseases. Here we show that a variable proportion of CD8
T cells compartmentalized in the human liver co-stain for CD14 and other prototypic myeloid membrane proteins and are enriched in close proximity to CD14
myeloid cells in hepatic zone 2. CD14
CD8
T cells preferentially accumulate within the donor pool in liver allografts, among hepatic virus-specific and tumour-infiltrating responses, and in cirrhotic ascites. CD14
CD8
T cells exhibit increased turnover, activation and constitutive immunomodulatory features with high homeostatic IL-10 and IL-2 production ex vivo, and enhanced antiviral/anti-tumour effector function after TCR engagement. This CD14
CD8
T cell profile can be recapitulated by the acquisition of membrane proteins-including the lipopolysaccharide receptor complex-from mononuclear phagocytes, resulting in augmented tumour killing by TCR-redirected T cells in vitro. CD14
CD8
T cells express integrins and chemokine receptors that favour interactions with the local stroma, which can promote their induction through CXCL12. Lipopolysaccharide can also increase the frequency of CD14
CD8
T cells in vitro and in vivo, and skew their function towards the production of chemotactic and regenerative cytokines. Thus, bacterial products in the gut-liver axis and tissue stromal factors can tune liver immunity by driving myeloid instruction of CD8
T cells with immunomodulatory ability.
Objective
Ophthalmic complications in Systemic Lupus Erythematosus (SLE) are broad and can occur in up to a third of patients. The British Isles Lupus Assessment Group (BILAG) 2004 Index identifies ...13 ocular manifestations of active SLE, as opposed to those related to previous disease activity and/or the consequences of therapy. We conducted a systematic review of published literature to determine the frequency of ophthalmic manifestations of active SLE.
Methods
A systematic literature search of Ovid MEDLINE and EMBASE from their respective inceptions to July 2020 was conducted to identify cohort, case–control and cross-sectional studies.
Results
22 studies meeting eligibility criteria were included. Most studies featured small sample sizes and were judged to have a high risk of methodological bias. The number and quality of studies did not allow us to confidently estimate the incidence of the conditions. No studies reported epidemiological data for orbital inflammation/myositis/proptosis. The prevalence of each of the other ocular manifestations, with the exception of retinal vaso-occlusive disease, was consistently less than 5%. Retinal vasculitis, uveitis and isolated cotton wool spots tended to be associated with more active SLE disease.
Conclusion
The prevalence of eye disease due to SLE activity is uncommon, but clinicians should be aware that some conditions tend to be associated with more active systemic disease. Further studies to determine the incidence and risk factors for these ophthalmic manifestations are needed.
Background
The decision for emergent and urgent ventral hernia repair (VHR) is driven by acute symptomatology, concern for incarceration and strangulation, and perforation. Although mesh has been ...established to reduce hernia recurrences, the potential for mesh complications may impact the decision for utilization in emergent repairs. This study evaluates hernia repair outcomes in the emergent setting with/without mesh.
Methods
An IRB-approved review of NSQIP and retrospective chart review data of emergent/urgent VHRs performed between 2013 and 2017 was conducted at a single academic institution. Six-month postoperative emergency department and surgery clinic visits, hospital readmissions, and hernia recurrences were recorded. Patients were grouped based on mesh utilization. Perioperative and outcome variables were compared using Chi-square, Fisher’s exact, and t-tests.
Results
Among 94 patients, 41 (44%) received mesh; 53 (56%) did not. Synthetic mesh was used in 27 cases (65.9%); bioresorbable or biologic mesh was used in 14 cases (34.1%). ASA class (
p
= 0.016) was higher in the no-mesh group, as were emergent vs. urgent cases (
p
≤ 0.001). Preoperative SIRS/Sepsis, COPD, and diabetes were increased in the no-mesh group. Hernia recurrence was significantly higher in the no-mesh group vs. the mesh group (24.5% vs. 7.3%,
p
= 0.03). No difference was found in wound complications between groups. ED visits occurred almost twice as often in the mesh group (42% vs. 23%,
p
= 0.071). Postoperative surgery clinic visits were more frequent among the mesh group (> 1 visit 61% vs. 24%,
p
= 0.004).
Conclusions
Mesh-based hernia repairs in the urgent/emergent patient population are performed in fewer than half of patients in our tertiary care referral center. Repairs without mesh were associated with over a three-fold increase in recurrence without a difference in the risk of infectious complications. Efforts to understand the rationale for suture-based repair compared to mesh repair are needed to reduce hernia recurrences in the emergent population.
Cochlear implantation leads to many structural changes within the cochlea which can impair residual hearing. In patients with preserved low-frequency hearing, a delayed hearing loss can occur ...weeks-to-years post-implantation. We explore whether stiffening of the basilar membrane (BM) may be a contributory factor in an animal model. Our objective is to map changes in morphology and Young’s modulus of basal and apical areas of the BM after cochlear implantation, using quantitative nanomechanical atomic force microscopy (QNM-AFM) after cochlear implant surgery. Cochlear implantation was undertaken in the guinea pig, and the BM was harvested at four time-points: 1 day, 14 days, 28 days and 84 days post-implantation for QNM-AFM analysis. Auditory brainstem response thresholds were determined prior to implantation and termination. BM tissue showed altered morphology and a progressive increase in Young’s modulus, mainly in the apex, over time after implantation. BM tissue from the cochlear base demonstrated areas of extreme stiffness which are likely due to micro-calcification on the BM. In conclusion, stiffening of the BM after cochlear implantation occurs over time, even at sites far apical to a cochlear implant.
•Mechanical and topological changes following cochlear implantation were identified.•After implantation in the base, the apical basilar membrane progressively stiffened.•In the base, numerous (9% surface) hyper-dense stiff deposits were found at 84 days.•Hearing thresholds increased, maximally at 28 days for 8–32 kHz, 84 days for 2 kHz.•The data suggest micro-calcification in the base and micro-scarring in the apex.
Purpose To cross-validate T1-weighted oxygen-enhanced (OE) MRI measurements of tumor hypoxia with intrinsic susceptibility MRI measurements and to demonstrate the feasibility of translation of the ...technique for patients. Materials and Methods Preclinical studies in nine 786-0-R renal cell carcinoma (RCC) xenografts and prospective clinical studies in eight patients with RCC were performed. Longitudinal relaxation rate changes (∆R1) after 100% oxygen inhalation were quantified, reflecting the paramagnetic effect on tissue protons because of the presence of molecular oxygen. Native transverse relaxation rate (R2*) and oxygen-induced R2* change (∆R2*) were measured, reflecting presence of deoxygenated hemoglobin molecules. Median and voxel-wise values of ∆R1 were compared with values of R2* and ∆R2*. Tumor regions with dynamic contrast agent-enhanced MRI perfusion, refractory to signal change at OE MRI (referred to as perfused Oxy-R), were distinguished from perfused oxygen-enhancing (perfused Oxy-E) and nonperfused regions. R2* and ∆R2* values in each tumor subregion were compared by using one-way analysis of variance. Results Tumor-wise and voxel-wise ∆R1 and ∆R2* comparisons did not show correlative relationships. In xenografts, parcellation analysis revealed that perfused Oxy-R regions had faster native R2* (102.4 sec
vs 81.7 sec
) and greater negative ∆R2* (-22.9 sec
vs -5.4 sec
), compared with perfused Oxy-E and nonperfused subregions (all P < .001), respectively. Similar findings were present in human tumors (P < .001). Further, perfused Oxy-R helped identify tumor hypoxia, measured at pathologic analysis, in both xenografts (P = .002) and human tumors (P = .003). Conclusion Intrinsic susceptibility biomarkers provide cross validation of the OE MRI biomarker perfused Oxy-R. Consistent relationship to pathologic analyses was found in xenografts and human tumors, demonstrating biomarker translation. Published under a CC BY 4.0 license. Online supplemental material is available for this article.
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Ligands for the bromodomain and extra-terminal domain (BET) family of bromodomains have shown promise as useful therapeutic agents for treating a range of cancers and inflammation. ...Here we report that our previously developed 3,5-dimethylisoxazole-based BET bromodomain ligand (OXFBD02) inhibits interactions of BRD4(1) with the RelA subunit of NF-κB, in addition to histone H4. This ligand shows a promising profile in a screen of the NCI-60 panel but was rapidly metabolised (t½ = 39.8 min). Structure-guided optimisation of compound properties led to the development of the 3-pyridyl-derived OXFBD04. Molecular dynamics simulations assisted our understanding of the role played by an internal hydrogen bond in altering the affinity of this series of molecules for BRD4(1). OXFBD04 shows improved BRD4(1) affinity (IC50 = 166 nM), optimised physicochemical properties (LE = 0.43; LLE = 5.74; SFI = 5.96), and greater metabolic stability (t½ = 388 min).
Zero‐deforestation commitments seek to decouple agricultural production and forest loss to improve prospects for biodiversity. However, the effectiveness of methods designed to meet these commitments ...is poorly understood. In a highly fragmented tropical landscape dominated by oil palm, we tested the capacity for the High Carbon Stock (HCS) Approach to prioritize forest remnants that sustain mammal diversity. Patches afforded high priority by HCS protocols (100 ha core area) provided important refuges for IUCN‐threatened species and megafauna. However, patch‐scale HCS area recommendations conserved only 35% of the mammal community. At least 3,000 ha would be required to retain intact mammal assemblages, with nearly 10 times this area needed if hunting pressure was high. While current HCS protocols will safeguard patches capable of sustaining biodiversity, highly fragmented tropical landscapes typical of zero‐deforestation pledges will require thinking beyond the patch toward strategically configured forest remnants at the landscape level and enforcing strict controls on hunting.
Target validation remains a challenge in drug discovery, which leads to a high attrition rate in the drug discovery process, particularly in Phase II clinical trials. Consequently, new approaches to ...enhance target validation are valuable tools to improve the drug discovery process. Here, we report the combination of site-directed mutagenesis and electrophilic fragments to enable the rapid identification of small molecules that selectively inhibit the mutant protein. Using the bromodomain-containing protein BRD4 as an example, we employed a structure-based approach to identify the L94C mutation in the first bromodomain of BRD4 BRD4(1) as having a minimal effect on BRD4(1) function. We then screened a focused, KAc mimic-containing fragment set and a diverse fragment library against the mutant and wild-type proteins and identified a series of fragments that showed high selectivity for the mutant protein. These compounds were elaborated to include an alkyne click tag to enable the attachment of a fluorescent dye. These clickable compounds were then assessed in HEK293T cells, transiently expressing BRD4(1)WT or BRD4(1)L94C, to determine their selectivity for BRD4(1)L94C over other possible cellular targets. One compound was identified that shows very high selectivity for BRD4(1)L94C over all other proteins. This work provides a proof-of-concept that the combination of site-directed mutagenesis and electrophilic fragments, in a mutate and conjugate approach, can enable rapid identification of small molecule inhibitors for an appropriately mutated protein of interest. This technology can be used to assess the cellular phenotype of inhibiting the protein of interest, and the electrophilic ligand provides a starting point for noncovalent ligand development.
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