Repeatability of MRI Biomarkers in Nonalcoholic Fatty Liver Disease: The NIMBLE Consortium.

Background There is a need for reliable noninvasive methods for diagnosing and monitoring nonalcoholic fatty liver disease (NAFLD). Thus, the multidisciplinary Non-invasive Biomarkers of Metabolic Liver disease (NIMBLE) consortium was formed to identify and advance the regulatory qualification of NAFLD imaging biomarkers. Purpose To determine the different-day same-scanner repeatability coefficient of liver MRI biomarkers in patients with NAFLD at risk for steatohepatitis. Materials and Methods NIMBLE 1.2 is a prospective, observational, single-center short-term cross-sectional study (October 2021 to June 2022) in adults with NAFLD across a spectrum of low, intermediate, and high likelihood of advanced fibrosis as determined according to the fibrosis based on four factors (FIB-4) index. Participants underwent up to seven MRI examinations across two visits less than or equal to 7 days apart. Standardized imaging protocols were implemented with six MRI scanners from three vendors at both 1.5 T and 3 T, with central analysis of the data performed by an independent reading center (University of California, San Diego). Trained analysts, who were blinded to clinical data, measured the MRI proton density fat fraction (PDFF), liver stiffness at MR elastography (MRE), and visceral adipose tissue (VAT) for each participant. Point estimates and CIs were calculated using χ2 distribution and statistical modeling for pooled repeatability measures. Results A total of 17 participants (mean age, 58 years ± 8.5 [SD]; 10 female) were included, of which seven (41.2%), six (35.3%), and four (23.5%) participants had a low, intermediate, or high likelihood of advanced fibrosis, respectively. The different-day same-scanner mean measurements were 13%-14% for PDFF, 6.6 L for VAT, and 3.15 kPa for two-dimensional MRE stiffness. The different-day same-scanner repeatability coefficients were 0.22 L (95% CI: 0.17, 0.29) for VAT, 0.75 kPa (95% CI: 0.6, 0.99) for MRE stiffness, 1.19% (95% CI: 0.96, 1.61) for MRI PDFF using magnitude reconstruction, 1.56% (95% CI: 1.26, 2.07) for MRI PDFF using complex reconstruction, and 19.7% (95% CI: 15.8, 26.2) for three-dimensional MRE shear modulus. Conclusion This preliminary study suggests that thresholds of 1.2%-1.6%, 0.22 L, and 0.75 kPa for MRI PDFF, VAT, and MRE, respectively, should be used to discern measurement error from real change in patients with NAFLD. ClinicalTrials.gov registration no. NCT05081427 © RSNA, 2023 Supplemental material is available for this article. See also the editorial by Kozaka and Matsui in this issue.

Diagnostic performance of circulating biomarkers for non-alcoholic steatohepatitis.

There are no approved diagnostic biomarkers for at-risk non-alcoholic steatohepatitis (NASH), defined by the presence of NASH, high histological activity and fibrosis stage ≥2, which is associated with higher incidence of liver-related events and mortality. FNIH-NIMBLE is a multi-stakeholder project to support regulatory approval of NASH-related biomarkers. The diagnostic performance of five blood-based panels was evaluated in an observational (NASH CRN DB2) cohort (n = 1,073) with full spectrum of non-alcoholic fatty liver disease (NAFLD). The panels were intended to diagnose at-risk NASH (NIS4), presence of NASH (OWLiver) or fibrosis stages >2, >3 or 4 (enhanced liver fibrosis (ELF) test, PROC3 and FibroMeter VCTE). The prespecified performance metric was an area under the receiver operating characteristic curve (AUROC) ≥0.7 and superiority over alanine aminotransferase for disease activity and the FIB-4 test for fibrosis severity. Multiple biomarkers met these metrics. NIS4 had an AUROC of 0.81 (95% confidence interval: 0.78-0.84) for at-risk NASH. The AUROCs of the ELF test, PROC3 and FibroMeterVCTE for clinically significant fibrosis (≥stage 2), advanced fibrosis (≥stage 3) or cirrhosis (stage 4), respectively, were all ≥0.8. ELF and FibroMeter VCTE outperformed FIB-4 for all fibrosis endpoints. These data represent a milestone toward qualification of several biomarker panels for at-risk NASH and also fibrosis severity in individuals with NAFLD.

Tofacitinib Reduces Spinal Inflammation in Vertebral Bodies and Posterolateral Elements in Ankylosing Spondylitis: Results from a Phase 2 Trial.

INTRODUCTION: This post hoc analysis of phase 2 trial data assessed the efficacy of tofacitinib on magnetic resonance imaging (MRI) outcomes with the detailed anatomy-based Canada-Denmark (CANDEN) MRI scoring system and evaluated tofacitinib suppression of spinal inflammation in patients with active ankylosing spondylitis (AS). METHODS: Patients with active AS (per modified New York criteria) were randomized 1:1:1:1 to receive tofacitinib 2, 5, or 10 mg twice daily (BID), or placebo, in a 16-week, phase 2, double-blind clinical trial. Spine MRI assessments were performed at baseline and week 12. For post hoc analysis, MRI images from patients receiving tofacitinib 5 or 10 mg BID, or placebo, were re-evaluated by two readers blinded to time point/treatment and assessed by the CANDEN MRI scoring system. Least squares mean changes from baseline to week 12 were reported for CANDEN-specific MRI outcomes, with analysis of covariance used for comparisons of pooled tofacitinib and tofacitinib 5 or 10 mg BID versus placebo. p values without multiplicity adjustment were reported. RESULTS: MRI data from 137 patients were analyzed. At week 12, CANDEN spine inflammation score and vertebral body, posterior elements, corner, non-corner, facet joint, and posterolateral inflammation subscores were significantly reduced with pooled tofacitinib versus placebo (p < 0.0001; except non-corner subscore, p < 0.05). Total spine fat score was numerically increased with pooled tofacitinib versus placebo. CONCLUSIONS: In patients with AS, tofacitinib treatment was associated with significant reductions in MRI scores of spinal inflammation versus placebo, as assessed by the CANDEN MRI scoring system. Tofacitinib reduced inflammation in posterolateral elements of the spine and facet joints, which has not been described previously. TRIAL REGISTRATION: ClinicalTrials.gov registry (NCT01786668).

The Nimble Stage 1 Study Validates Diagnostic Circulating Biomarkers for Nonalcoholic Steatohepatitis.

Background There are no approved noninvasive tests (NIT) for the diagnosis of nonalcoholic steatohepatitis (NASH) and its histological phenotypes. Methods The FNIH-NIMBLE consortium tested 5 serum-based NIT panels for the following intended uses: NIS4: At-risk NASH, a composite of NASH with NAFLD activity score (NAS) ≥ 4 and fibrosis stage ≥ 2, OWLiver: NASH and NAS ≥ 4, enhanced liver fibrosis (ELF), PROC3 and Fibrometer VCTE: fibrosis stages ≥ 2, ≥ 3 or 4. Aliquots from a single blood sample obtained within 90 days of histological confirmation of NAFLD were tested. The prespecified performance metric tested for was a diagnostic AUROC greater than 0.7 and superiority to ALT for diagnosis of NASH or NAS ≥ 4 and to FIB-4 for fibrosis. Results A total of 1073 adults including NASH (n = 848), at-risk NASH (n = 539) and fibrosis stages 0-4 (n = 222, 114, 262, 277 and 198 respectively) were studied. The AUROC of NIS4 for at-risk NASH was 0.81 and superior to ALT and FIB4 (p < 0.001 for both). OWliver diagnosed NASH with sensitivity and specificity of 77.3% and 66.8% respectively. The AUROCs (95% CI) of ELF, PROC3 and Fibrometer VCTE respectively for fibrosis were as follows: ≥ stage 2 fibrosis [0.82 (0.8-0.85), 0.8 (0.77-0.83), and 0.84 (0.79-0.88)], ≥ stage 3 [0.83 (0.8-0.86), 0.76 (0.73-0.79), 0.85 (0.81-0.9), stage 4 [0.85 (0.81-0.89), 0.81 (0.77-0.85), 0.89 (0.84-0.95)]. ELF and Fibrometer VCTE were significantly superior to FIB-4 for all fibrosis endpoints (p < 0.01 for all). Conclusions These data support the further development of NIS4, ELF and Fibrometer VCTE for their intended uses.

How perceived maternal gatekeeping affects fathers: An 8-week study.

Maternal gatekeeping describes mothers' attempts to influence father involvement in child-rearing. While the effect of maternal gatekeeping on the father-child relationship has been explored, less is known about how fluctuations in the perception of maternal gatekeeping influences fathers' family outcomes and whether father's attachment might moderate these associations. Building on family systems theory, this study explores the within-person effect of negative maternal gatekeeping on father's weekly reports of romantic relationship quality and feelings of exclusion from the family and tests father attachment as a moderator of these associations. Two hundred seventy-seven Canadian and German fathers with children under the age of 6 took part in an 8-week online diary study. Data were analyzed using multilevel structural equation modeling. During weeks when fathers perceived more maternal gatekeeping than was typical, they reported lower positive romantic relationship quality, higher negative romantic relationship quality, and felt more excluded from the family system. Avoidant attachment moderated the within-person effect of perceived maternal gatekeeping on negative romantic relationship quality, such that within-person increases in perceived maternal gatekeeping were more strongly linked with higher than-average negative romantic relationship quality among more avoidant fathers. Our findings shed new light on the within-person effects of perceived maternal gatekeeping on fathers' feelings regarding the family system. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Dual-energy X-ray absorptiometry measures of lean body mass as a biomarker for progression in boys with Duchenne muscular dystrophy.

We evaluated whether whole-body dual-energy X-ray absorptiometry (DXA) measures of lean body mass can be used as biomarkers for disease progression and treatment effects in patients with Duchenne muscular dystrophy. This post hoc analysis utilized data from a randomized, 2-period study of domagrozumab versus placebo in 120 ambulatory boys with DMD. DXA measures of lean body mass were obtained from the whole body (excluding head), arms, legs and appendicular skeleton at baseline and every 16 weeks. Treatment effects on DXA measures for domagrozumab versus placebo were assessed at Week 49. At Week 49, domagrozumab statistically significantly increased lean body mass versus placebo in the appendicular skeleton (p = 0.050) and arms (p < 0.001). The relationship between lean body mass at Week 49 and functional endpoints at Week 97 was evaluated. Changes in lean body mass at Week 49 in all regions except arms were significantly correlated with percent change from baseline in 4-stair climb (4SC) at Week 97. DXA-derived percent lean mass at Week 49 also correlated with 4SC and North Star Ambulatory Assessment at Week 97. These data indicate that whole-body DXA measures can be used as biomarkers for treatment effects and disease progression in patients with DMD, and warrant further investigation.Trial registration: ClinicalTrials.gov, NCT02310763; registered 8 December 2014.

Quantitative magnetic resonance imaging measures as biomarkers of disease progression in boys with Duchenne muscular dystrophy: a phase 2 trial of domagrozumab.

Duchenne muscular dystrophy (DMD) is a progressive, neuromuscular disorder caused by mutations in the DMD gene that results in a lack of functional dystrophin protein. Herein, we report the use of quantitative magnetic resonance imaging (MRI) measures as biomarkers in the context of a multicenter phase 2, randomized, placebo-controlled clinical trial evaluating the myostatin inhibitor domagrozumab in ambulatory boys with DMD (n = 120 aged 6 to < 16 years). MRI scans of the thigh to measure muscle volume, muscle volume index (MVI), fat fraction, and T2 relaxation time were obtained at baseline and at weeks 17, 33, 49, and 97 as per protocol. These quantitative MRI measurements appeared to be sensitive and objective biomarkers for evaluating disease progression, with significant changes observed in muscle volume, MVI, and T2 mapping measures over time. To further explore the utility of quantitative MRI measures as biomarkers to inform longer term functional changes in this cohort, a regression analysis was performed and demonstrated that muscle volume, MVI, T2 mapping measures, and fat fraction assessment were significantly correlated with longer term changes in four-stair climb times and North Star Ambulatory Assessment functional scores. Finally, less favorable baseline measures of MVI, fat fraction of the muscle bundle, and fat fraction of lean muscle were significant risk factors for loss of ambulation over a 2-year monitoring period. These analyses suggest that MRI can be a valuable tool for use in clinical trials and may help inform future functional changes in DMD.Trial registration: ClinicalTrials.gov identifier, NCT02310763; registered December 2014.

Inter-Reader Consistency and Exclusionary Findings During Radiographic Screening for Phase 3 Trials of Tanezumab in Patients With Osteoarthritis.

Objective: Describe the radiograph-based screening program and frequencies of ineligibility in 3 large, international, randomized, double-blind, phase 3 studies of subcutaneous tanezumab in patients with osteoarthritis (OA). Design: Standardized bilateral shoulder, hip, and knee screening radiographs were obtained by trained imaging technologists and centrally read by 1 of 5 musculoskeletal radiology experts trained using a program-specific imaging atlas. Inter-reader consistency was tracked with test cases blindly inserted into the reader queue. Readers attended quarterly calibration meetings. Protocol-specified radiographic exclusion criteria included rapidly progressive OA (RPOA) or risk factors for RPOA (including severe malalignment of the knee, subchondral insufficiency fracture, atrophic OA, and osteonecrosis). Patients reporting disproportionate pain to radiographic evidence of OA in the hip or knee (without other pathology) were ineligible under a nonradiographic exclusion criterion. Results: At >480 international sites, 23,079 patients entered screening and 13,797 were radiographically assessed. Across 6 sets of quarterly testing, pairwise central reader agreement on radiographic eligibility was 72-87% (kappa: 0.41-0.71) and on radiographic OA grading 77-84% (kappa: 0.68-0.75). Among the 5,773/13,797 (41.8%) patients who met exclusionary criteria, 27% had disproportionate pain to radiographic findings (~10% of knee/hip radiographs). RPOA or risk factors for RPOA were each identified in <5% of patients (usually 1 joint) and <3% of knee/hip/shoulders. Conclusions: The phase 3 tanezumab screening program demonstrated the utility of radiographs to screen patients entering NGF inhibitor trials. A high degree of reader concordance was achieved. RPOA and risk factors for RPOA were not commonly observed. NCT02697773, NCT02709486, NCT02528188.

Quantitative muscle MRI biomarkers in Duchenne muscular dystrophy: cross-sectional correlations with age and functional tests.

Aim: Using baseline data from a clinical trial of domagrozumab in Duchenne muscular dystrophy, we evaluated the correlation between functional measures and quantitative MRI assessments of thigh muscle. Patients & methods: Analysis included timed functional tests, knee extension/strength and North Star Ambulatory Assessment. Patients (n = 120) underwent examinations of one thigh, with MRI sequences to enable measurements of muscle volume (MV), MV index, mean T2 relaxation time via T2-mapping and fat fraction. Results: MV was moderately correlated with strength assessments. MV index, fat fraction and T2-mapping measures had moderate correlations (r ∼ 0.5) to all functional tests, North Star Ambulatory Assessment and age. Conclusion: The moderate correlation between functional tests, age and baseline MRI measures supports MRI as a biomarker in Duchenne muscular dystrophy clinical trials. Trial registration: ClinicalTrials.gov, NCT02310763; registered 4 November 2014.

Lay abstract Clinical trials in Duchenne muscular dystrophy have proven to be challenging, due in part to the lack of robust biomarkers that are sensitive to detecting disease progression. While physical function, such as walking or climbing stairs, will be critical to demonstrating the long-term efficacy of a therapeutic, MRI may be a more objective approach that could detect subtle changes in disease status and offer earlier signals of clinical efficacy. In this study, researchers used baseline data from a Phase II clinical study (NCT02310763) to evaluate the relationship between measures of physical function and quantitative MRI assessments. They found that many MRI measures were moderately correlated with physical function, and muscle volume measurements were correlated with measures of strength. This study supports the use of MRI as a biomarker in Duchenne muscular dystrophy clinical trials.

A Middle Eocene lowland humid subtropical "Shangri-La" ecosystem in central Tibet.

Tibet's ancient topography and its role in climatic and biotic evolution remain speculative due to a paucity of quantitative surface-height measurements through time and space, and sparse fossil records. However, newly discovered fossils from a present elevation of ∼4,850 m in central Tibet improve substantially our knowledge of the ancient Tibetan environment. The 70 plant fossil taxa so far recovered include the first occurrences of several modern Asian lineages and represent a Middle Eocene (∼47 Mya) humid subtropical ecosystem. The fossils not only record the diverse composition of the ancient Tibetan biota, but also allow us to constrain the Middle Eocene land surface height in central Tibet to ∼1,500 ± 900 m, and quantify the prevailing thermal and hydrological regime. This "Shangri-La"-like ecosystem experienced monsoon seasonality with a mean annual temperature of ∼19 °C, and frosts were rare. It contained few Gondwanan taxa, yet was compositionally similar to contemporaneous floras in both North America and Europe. Our discovery quantifies a key part of Tibetan Paleogene topography and climate, and highlights the importance of Tibet in regard to the origin of modern Asian plant species and the evolution of global biodiversity.

Randomized phase 2 trial and open-label extension of domagrozumab in Duchenne muscular dystrophy.

We report results from a phase 2, randomized, double-blind, 2-period trial (48 weeks each) of domagrozumab and its open-label extension in patients with Duchenne muscular dystrophy (DMD). Of 120 ambulatory boys (aged 6 to <16 years) with DMD, 80 were treated with multiple ascending doses (5, 20, and 40 mg/kg) of domagrozumab and 40 treated with placebo. The primary endpoints were safety and mean change in 4-stair climb (4SC) time at week 49. Secondary endpoints included other functional tests, pharmacokinetics, and pharmacodynamics. Mean (SD) age was 8.4 (1.7) and 9.3 (2.3) years in domagrozumab- and placebo-treated patients, respectively. Difference in mean (95% CI) change from baseline in 4SC at week 49 for domagrozumab vs placebo was 0.27 (-7.4 to 7.9) seconds (p = 0.94). There were no significant between-group differences in any secondary clinical endpoints. Most patients had ≥1 adverse event in the first 48 weeks; most were mild and not treatment-related. Median serum concentrations of domagrozumab increased with administered dose within each dose level. Non-significant increases in muscle volume were observed in domagrozumab- vs placebo-treated patients. Domagrozumab was generally safe and well tolerated in patients with DMD. Efficacy measures did not support a significant treatment effect. Clinicaltrials.gov identifiers: NCT02310763 and NCT02907619.

Uplift, climate and biotic changes at the Eocene-Oligocene transition in south-eastern Tibet.

The uplift history of south-eastern Tibet is crucial to understanding processes driving the tectonic evolution of the Tibetan Plateau and surrounding areas. Underpinning existing palaeoaltimetric studies has been regional mapping based in large part on biostratigraphy that assumes a Neogene modernization of the highly diverse, but threatened, Asian biota. Here, with new radiometric dating and newly collected plant-fossil archives, we quantify the surface height of part of the south-eastern margin of Tibet in the latest Eocene (∼34 Ma) to be ∼3 km and rising, possibly attaining its present elevation (3.9 km) in the early Oligocene. We also find that the Eocene-Oligocene transition in south-eastern Tibet witnessed leaf-size diminution and a floral composition change from sub-tropical/warm temperate to cool temperate, likely reflective of both uplift and secular climate change, and that, by the latest Eocene, floral modernization on Tibet had already taken place, implying modernization was deeply rooted in the Palaeogene.

Tofacitinib is associated with attainment of the minimally important reduction in axial magnetic resonance imaging inflammation in ankylosing spondylitis patients.

Objectives: Minimally important changes (MICs) for SPondyloArthritis Research Consortium of Canada (SPARCC) MRI scores are ⩾2.5 for SI joint and ⩾5 for spine. This post hoc analysis assessed achievement of MIC in SPARCC scores in biologic-naïve patients with AS treated with tofacitinib or placebo, and correlation with clinical responses. Methods: Adult AS patients in a 12-week phase 2 study (n = 207) were randomized 1: 1: 1: 1 to tofacitinib 2, 5 or 10 mg twice daily (BID) or placebo. MIC in SPARCC SI joint and spine scores were assessed for patients with available MRI data (N = 164; 79%). Clinical endpoints at week 12, including Assessment of SpondyloArthritis international Society 20% improvement (ASAS20), were compared between patients achieving/not achieving MIC. Results: A greater proportion of patients achieved MIC with tofacitinib 2, 5 and 10 mg BID vs placebo for SI joint (28.6, 38.6, 29.6 vs 11.8%) and spine scores (29.3, 36.4, 40.9 vs 11.8%). Generally, a greater proportion of patients treated with tofacitinib 2, 5 and 10 mg BID or placebo, respectively, who achieved MIC for SI joint and spine scores achieved ASAS20 (SI joint: 75.0, 88.2, 69.2, 75.0%; spine: 91.7, 85.7, 72.2, 75.0%) vs patients who did not achieve MIC (SI joint: 51.7, 84.0, 58.1, 48.3%; spine: 46.4, 85.7, 53.8, 48.3%). Numerically greater responses were seen in those patients achieving vs not achieving MIC across a range of other efficacy assessments. Conclusion: Approximately one-third of tofacitinib-treated AS patients experienced clinically meaningful reductions in spinal MRI inflammation at week 12. Patients achieving MIC for MRI inflammation had greater clinical response.

Safety, Tolerability, Pharmacokinetics, and Pharmacodynamics of Domagrozumab (PF-06252616), an Antimyostatin Monoclonal Antibody, in Healthy Subjects.

Safety, tolerability, anabolic effects, pharmacokinetics, and pharmacodynamics of single ascending and multiple doses of domagrozumab, an antimyostatin monoclonal antibody, were assessed following intravenous (IV) and subcutaneous (SC) administration in healthy subjects. A range of single ascending dose levels between 1 and 40 mg/kg IV and multiple doses (3 doses) of 10 mg/kg IV were tested (n = 8 per cohort). Additionally, a 3 mg/kg SC (n = 8) cohort also received domagrozumab. Magnetic resonance imaging and whole-body dual-energy x-ray absorptiometry imaging were conducted to investigate the anabolic effects of domagrozumab. Domagrozumab was well tolerated with no severe and 1 non-treatment-related serious adverse event. The most commonly reported adverse events were headache (21 subjects) and fatigue, upper respiratory tract infections, and muscle spasms (10 subjects each). Domagrozumab demonstrated typical IgG1 pharmacokinetics, with slow SC absorption and slow clearance, low volume of distribution, and a long half-life. Target engagement was observed with an increase in extent of myostatin modulation, plateauing at the 20 mg/kg IV dose. Downstream pharmacology following myostatin binding by domagrozumab was only observed in the 10 mg/kg single IV cohort (increase in whole-body lean mass of 5.38% using dual-energy x-ray absorptiometry) and the 10 mg/kg repeat-dose cohort (muscle volume increase of 4.49% using magnetic resonance imaging).

Development of an imaging mitigation strategy for patient enrolment in the tanezumab nerve growth factor inhibitor (NGF-ab) program with a focus on eligibility assessment.

OBJECTIVE: Nerve growth factor antibodies (NGF-ab) have shown promising analgesic efficacy. Aim was to describe reader training efforts and present reliability data focusing on radiographic eligibility in the tanezumab program. METHODS: A multi-step process was used for reader calibration and reliability testing. First, a reference standard set of cases was created and diagnostic performance was evaluated. A second exercise focused on agreement of ordinal assessment (Kellgren-Lawrence grading) of radiographic osteoarthritis. Subsequently, 11 readers were trained and read a test set of 100 cases focused on eligibility assessments. Additional reliability testing and calibration of five core readers assessing eligibility of 30 cases was performed 3 and 6 months after study start. RESULTS: Sensitivity for the reference standard readings ranged from 0.50 to 0.90 and specificity from 0.40 to 0.83. Overall agreement for Kellgren-Lawrence grading ranged from 71.4% to 82.9%. For the 11 reader exercise, in 76% of cases at least 8 of 11 readers agreed on eligibility status. For the reliability testing 3 months after study start, in 80.0% of cases at least 4 of 5 readers agreed on eligibility with a κ = 0.43 (95% CI: 0.32-0.54). For the reliability testing after 6 months, in 83.3% of cases at least 4 of 5 readers agreed on eligibility with a κ = 0.52 (95% CI: 0.41-0.63). CONCLUSIONS: After intense efforts spent in the development of an imaging program for an NGF-ab clinical program, the achieved reliability for eligibility assessment is substantial but not perfect. Ongoing efforts of calibration prior to including additional readers to the program and during study conduct between current readers will be needed to ensure agreement on potential adverse events and radiographic disease severity.

Graphite-coated magnetic nanoparticle microarray for few-cells enrichment and detection.

Graphite-coated, highly magnetic FeCo core-shell nanoparticles were synthesized by a chemical vapor deposition method and solubilized in aqueous solution through a unique polymer mixture modification, which significantly improved the biocompatibility and stability of the magnetic nanoparticles (MNPs). Such functionalized MNPs were proven to be very stable in different conditions which would be significant for biological applications. Cell staining, manipulation, enrichment, and detection were developed with these MNPs. Under external magnetic manipulation, the MNP-stained cells exhibited directed motions. Moreover, MNPs were printed on substrates to modulate the magnetic field distribution on the surface. Capture and detection of sparse populations of cancer cells spiked into whole blood has been explored in a microarray fashion. Cancer cells from hundreds down to only two were able to be simply and efficiently detected from 1 mL of whole blood on the MNP microarray chips. Interestingly, the cells captured through the MNP microarray still showed viability and adhered to the MNP spots after incubation, which could be utilized for cancer cell detection, localized growth, and proliferation.

Near infrared imaging and photothermal ablation of vascular inflammation using single-walled carbon nanotubes.

BACKGROUND: Macrophages are critical contributors to atherosclerosis. Single-walled carbon nanotubes (SWNTs) show promising properties for cellular imaging and thermal therapy, which may have application to vascular macrophages. METHODS AND RESULTS: In vitro uptake and photothermal destruction of mouse macrophage cells (RAW264.7) were performed with SWNTs (14.7 nmol/L) exposed to an 808-nm light source. SWNTs were taken up by 94 ± 6% of macrophages, and light exposure induced 93 ± 3% cell death. In vivo vascular macrophage uptake and ablation were then investigated in carotid-ligated FVB mice (n=33) after induction of hyperlipidemia and diabetes. Two weeks postligation, near-infrared fluorescence (NIRF) carotid imaging (n=12) was performed with SWNT-Cy5.5 (8 nmol of Cy5.5) given via the tail vein. Photothermal heating and macrophage apoptosis were evaluated on freshly excised carotid arteries (n=21). NIRF of SWNTs showed higher signal intensity in ligated carotids compared with sham, confirmed by both in situ and ex vivo NIRF imaging (P<0.05, ligation versus sham). Immunofluorescence staining showed colocalization of SWNT-Cy5.5 and macrophages in atherosclerotic lesions. Light (808 nm) exposure of freshly excised carotids showed heating and induction of macrophage apoptosis in ligated left carotid arteries with SWNTs, but not in control groups without SWNTs or without light exposure. CONCLUSIONS: Carbon nanotubes accumulate in atherosclerotic macrophages in vivo and provide a multifunctional platform for imaging and photothermal therapy of vascular inflammation.

Plasmonic substrates for multiplexed protein microarrays with femtomolar sensitivity and broad dynamic range.

Protein chips are widely used for high-throughput proteomic analysis, but to date, the low sensitivity and narrow dynamic range have limited their capabilities in diagnostics and proteomics. Here we present protein microarrays on a novel nanostructured, plasmonic gold film with near-infrared fluorescence enhancement of up to 100-fold, extending the dynamic range of protein detection by three orders of magnitude towards the fM regime. We employ plasmonic protein microarrays for the early detection of a cancer biomarker, carcinoembryonic antigen, in the sera of mice bearing a xenograft tumour model. Further, we demonstrate a multiplexed autoantigen array for human autoantibodies implicated in a range of autoimmune diseases with superior signal-to-noise ratios and broader dynamic range compared with commercial nitrocellulose and glass substrates. The high sensitivity, broad dynamic range and easy adaptability of plasmonic protein chips presents new opportunities in proteomic research and diagnostics applications.