Dataset Information

Quantification and monitoring of inflammation in murine inflammatory bowel disease with targeted contrast-enhanced US.

ABSTRACT:

Purpose

To evaluate ultrasonography (US) by using contrast agent microbubbles (MBs) targeted to P-selectin (MB(P-selectin)) to quantify P-selectin expression levels in inflamed tissue and to monitor response to therapy in a murine model of chemically induced inflammatory bowel disease (IBD).

Materials and methods

All procedures in which laboratory animals were used were approved by the institutional administrative panel on laboratory animal care. Binding affinity and specificity of MB(P-selectin) were tested in cell culture experiments under flow shear stress conditions and compared with control MBs (MB(Control)). In vivo binding specificity of MB(P-selectin) to P-selectin was tested in mice with trinitrobenzenesulfonic acid-induced colitis (n = 22) and control mice (n = 10). Monitoring of anti-tumor necrosis factor α antibody therapy was performed over 5 days in an additional 30 mice with colitis by using P-selectin-targeted US imaging, by measuring bowel wall thickness and perfusion, and by using a clinical disease activity index score. In vivo targeted contrast material-enhanced US signal was quantitatively correlated with ex vivo expression levels of P-selectin as assessed by quantitative immunofluorescence.

Results

Attachment of MB(P-selectin) to endothelial cells was significantly (P = .0001) higher than attachment of MB(Control) and significantly (ρ = 0.83, P = .04) correlated with expression levels of P-selectin on endothelial cells. In vivo US signal in mice with colitis was significantly higher (P = .0001) with MB(P-selectin) than with MB(Control). In treated mice, in vivo US signal decreased significantly (P = .0001) compared with that in nontreated mice and correlated well with ex vivo P-selectin expression levels (ρ = 0.69; P = .04). Colonic wall thickness (P ≥ .06), bowel wall perfusion (P ≥ .85), and clinical disease activity scoring (P ≥ .06) were not significantly different between treated and nontreated mice at any time.

Conclusion

Targeted contrast-enhanced US imaging enables noninvasive in vivo quantification and monitoring of P-selectin expression in inflammation in murine IBD.

SUBMITTER: Deshpande N

PROVIDER: S-EPMC3244669 | biostudies-literature |

REPOSITORIES: biostudies-literature

ACCESS DATA

Similar Datasets

Project description:Articular cartilage lines the load-bearing surfaces of long bones and undergoes compositional and structural degeneration during osteoarthritis progression. Contrast enhanced microcomputed tomography (?CT) is being applied to a variety of preclinical models, including the mouse, to map structural and compositional properties in 3-D. The thinness (?30-50??m) and high cellularity of mouse articular cartilage presents a significant imaging challenge. Our group previously showed that mouse articular cartilage and proteoglycan (PG) content can be assessed by ?CT with the ioxagalate-based contrast agent Hexabrix, but the voxel size used (6??m) was deemed to be barely adequate. The objective of the present study is to assess the utility of a novel contrast agent, CA4+, to quantify mouse articular cartilage morphology and composition with high resolution ?CT imaging (3??m voxels) and to compare the sensitivity of CA4+ and Hexabrix to detect between-group differences. While both contrast agents are iodine-based, Hexabrix is anionic and CA4+ is cationic so they interact differently with negatively charged PGs. With CA4+, a strong correlation was found between non-calcified articular cartilage thickness measurements made with histology and ?CT (R2 ?=?0.72, p?<?0.001). Cartilage degeneration-as assessed by loss in volume, thickness, and PG content-was observed in 34-week-old mice when compared to both 7- and 12-week-old mice. High measurement precision was observed with CA4+, with the coefficient of variation after repositioning and re-imaging samples equaling 2.8%, 4.5%, 7.4% and 5.9% for attenuation, thickness, volume, and PG content, respectively. Use of CA4+ allowed increased sensitivity for assessing PG content compared to Hexabrix, but had no advantage for measurement of cartilage thickness or volume. This improvement in imaging should prove useful in preclinical studies of cartilage degeneration and regeneration. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:2740-2748, 2017.

Project description:BACKGROUND:We assessed practice patterns for monitoring mucosal inflammation after biologic initiation and the association between monitoring approaches and development of disease-related complications for Crohn's disease (CD) and ulcerative colitis (UC). METHODS:This study used a Truven Health MarketScan (2007-2016) query for CD and UC patients initiating biologic therapy. Cumulative 24-month disease-related complications (corticosteroids, change of biologic, hospitalization, surgery) in patients undergoing proactive disease monitoring with lower endoscopy, fecal calprotectin, or cross-sectional radiographic enterography (computed tomography enterography or magnetic resonance enterography) within 6 months of biologic initiation vs no early monitoring after biologic initiation were compared. Cox proportional hazard ratios (HRs with 95% confidence intervals [CIs]) adjusted for propensity score were used. RESULTS:Within the first 24 months after biologic initiation, monitoring (proactive or reactive) was performed in 56.4% of CD patients and 67.8% of UC patients, with considerable geographic variability. Early (within 6 months) proactive monitoring was endoscopy-based (87.9%), performed in 11% of CD (n = 2195/19,899) and 12.8% of UC (n = 925/7247) patients. Compared with no early monitoring, early proactive monitoring was associated with a reduction in disease-related complications for CD (adjusted HR [aHR], 0.90; 95% CI, 0.84-0.96) and UC (aHR, 0.87; 95% CI, 0.78-0.97) and predominately driven by a reduction in corticosteroid use (CD: aHR, 0.83; 95% CI, 0.77-0.90; UC: aHR, 0.77; 95% CI, 0.69-0.87). Results were consistent across multiple sensitivity analyses. CONCLUSIONS:Early proactive monitoring of mucosal inflammation in CD and UC within 6 months of biologic initiation was associated with reduction in disease-related complications over 24 months, primarily related to reduced steroid utilization. Wide variation exists in practice patterns for monitoring of mucosal inflammation after biologic initiation.

Project description:To develop and test a molecular imaging approach that uses ultrasonography (US) and a clinically translatable dual-targeted (P- and E-selectin) contrast agent (MBSelectin) in the quantification of inflammation at the molecular level and to quantitatively correlate selectin-targeted US with fluorodeoxyglucose (FDG) combined positron emission tomography (PET) and computed tomography (CT) in terms of visualization and quantification of different levels of inflammation in a murine acute colitis model.Animal studies were approved by the Institutional Administrative Panel on Laboratory Animal Care at Stanford University. MBSelectin was developed by covalently binding an analog of the naturally occurring binding ligand P-selectin glycoprotein ligand 1 fused to a human fragment crystallizable(or Fc) domain onto the lipid shell of perfluorobutane and nitrogen-containing MBs. Binding specificity of MBSelectin was assessed in vitro with a flow chamber assay and in vivo with a chemically induced acute colitis murine model. US signal was quantitatively correlated with FDG uptake at PET/CT and histologic grade. Statistical analysis was performed with the Student t test, analysis of variance, and Pearson correlation analysis.MBSelectin showed strong attachment to both human and mouse P- and E-selectin compared with MBControl in vitro (P ? .002). In vivo, US signal was significantly increased (P < .001) in mice with acute colitis (173.8 arbitrary units [au] ± 134.8 [standard deviation]) compared with control mice (5.0 au ± 4.5). US imaging signal strongly correlated with FDG uptake on PET/CT images (? = 0.89, P < .001). Ex vivo analysis enabled confirmation of inflammation in mice with acute colitis and high expression levels of P- and E-selectin in mucosal capillaries (P = .014).US with MBSelectin specifically enables detection and quantification of inflammation in a murine acute colitis model, leveraging the natural pathway of leukocyte recruitment in inflammatory tissue. US imaging with MBSelectin correlates well with FDG uptake at PET/CT imaging.