Detection of Radiolabeled Inflammatory Cell Macrophage Subpopulations in Chronic Respiratory Diseases: Results from Preliminary Analyses.

Chronic respiratory diseases (CRDs) like asthma and chronic obstructive pulmonary disease (COPD) are the leading causes of morbidity and mortality worldwide. Alveolar macrophages (AM) are immune cells that exist in different polarization states/phenotypes and have been shown to play a critical role during an inflammatory process. In this paper, differently polarized mouse bone marrow-derived macrophages (BMDM (M1-proinflammatory or M2-immunomodulator)) were radiolabeled with either 99mTc-D,L-hexamethylene-propyleneamine oxime (99mTc-HMPAO), 2-deoxy-2-[18F] fluoro-D-glucose (18F-FDG), or 67Ga-citrate. Biocompatibility and in vivo biodistribution of radionuclide-labeled macrophages after intravenous injection were evaluated. Radioactivity measurements were performed using Packard Cobra Quantum 5002 Gamma Counter. Both M1 and M2 macrophages showed a higher uptake for 18F-FDG and 99mTc-HMPAO, than 67Ga-citrate. M2 macrophages showed a higher uptake of radionuclides than M1 macrophages. The used radionuclides were biocompatible for both M1 and M2 macrophages. At 2-hour postinjection, 18F-FDG-labeled M1 and M2 macrophages were found significantly higher in the lung of inflammatory animals (12.54 ± 1.58% and 14.13 ± 1.03%, respectively) than in control mice. Labeling macrophages with either 18F-FDG or 99mTc-HMPAO did not affect their biodistribution. The results from these initial experiments indicate that radionuclide-labeled macrophages may allow a higher sensitivity detection in nuclear imaging techniques such as PET and SPECT. Further confirmatory studies are needed to noninvasively image radiolabeled BMDM to understand their role in the inflammatory processes inherent to CRDs.

Expression of VEGF, EGF and HGF in early- and late-stage colorectal cancer.

The heterogenous nature of colorectal cancer (CRC) highlights the need for a better understanding of the growth factors that affect tumour growth and cancer progression. The aim of the present study was to evaluate the role of epidermal growth factor (EGF), vascular endothelial growth factor (VEGF) and hepatocyte growth factor (HGF) in the early (I and II) and late (III and IV) stages of CRC. The serum levels and mRNA expression (n=30) of the aforementioned growth factors were measured and immunohistochemistry (n=20) was performed in patients with CRC. Histological examination revealed comparable distribution of early-stage [I: 8 (26.7%) and II: 7 (23.3%)] and late-stage [III: 8 (26.7%) and IV: 7 (23.3%)] CRC. The mean serum concentrations of VEGF during the early (152.9±14.5 vs. 88.39±3.99 pg/ml; P=0.001) and late (182.7±25.8 vs. 88.39±3.99 pg/ml; P=0.002) stages were significantly higher compared with those in controls. Similarly, the mean serum concentrations of EGF in the early (409.4±7.96 vs. 153.7±13.8 pg/ml; P=0.05) and HGF in the late (90.4±17.4 vs. 56.9±4.97 pg/ml; P=0.05) stages were significantly higher compared with those in controls. The serum concentrations of VEGF, EGF and HGF were comparable between the early and late stages of CRC. Compared to normal tissues, the mRNA expression of both VEGF (P<0.001) and HGF (P<0.01) was upregulated in early-stage and downregulated in late-stage CRC. The expression of EGF remained significantly elevated during both the early and late stages of CRC (P<0.01). Histopathological analyses confirmed increased expression of VEGF in cancerous tissues compared with that in normal tissues. The present study emphasized the need for monitoring the serum levels and tissue expression of growth factors to fully elucidate their role in patients with CRC.

Gene expression patterns of COX-1, COX-2 and iNOS in H. Pylori infected histopathological conditions.

BACKGROUND: Research indicates that Helicobacter pylori can inflict severe histological damage through the modulation of host-related genes. The current study investigated the effect of H. pylori genotypes in the outcome of disease, and the expression of anti-apoptotic related genes, COX-1, COX-2, and iNOS genes in benign, pre-malignant, and malignant lesions of gastric carcinogenesis. MATERIALS AND METHODS: Tissue samples from H. pylori positive patients were graded based on the genotype of the infected H. pylori strain. Expression of COX-1, COX-2 and iNOS was assessed using a combination of real-time PCR and immunohistochemistry. RESULTS: Gene expression studies confirmed that COX-2 and iNOS expression was highly and selectively induced in epithelium with premalignant changes such as atrophic conditions, metaplasia and dysplasia, suggesting an important role of these genes in the sequence to gastric carcinoma of the intestinal type. Furthermore, the expression of COX-2 and iNOS was also dependent on the genotype of H. pylori and subjects with genotype-1 exhibited significantly higher expressions of COX-2 and iNOS compared to other genotypes. Comparison of the expression levels among infected and uninfected individuals demonstrated significant difference in the expression pattern of COX-2 gene whereas iNOS expression was found only in subjects infected H. pylori (p < 0.001). Immunohistochemical staining showed 1.5619 folds higher propensity of COX-2 and 3.2941 folds higher intensity of iNOS expression in subjects infected with H. pylori genotype 1. CONCLUSION: The up-regulation of COX-2 and iNOS was associated with the genotype of the H. pylori strain and the presence of certain genotype may greatly affect early events during carcinogenesis.

Vitamin D Receptor FokI, ApaI, and TaqI Polymorphisms in Lead Exposed Subjects From Saudi Arabia.

Vitamin D receptor (VDR) gene polymorphisms were reported to influence blood lead levels (BLL) and the response of subjects to the symptoms of lead toxicity. However, no studies have been conducted in the Saudi Arabian population which has unique ethnicity and socio-demographic features. This study examined the polymorphisms in exon 2 (allele 1) and intron 8 (allele 2 and allele 3) of VDR gene and their relation to BLLs. As per the CDC guidelines, the recruited lead-exposed workers (N = 130) were categorized to two groups viz., low BLL group (<10 µg/dL) and high BLL group (>10 µg/dL). The low BLL group had a mean BLL of 4.37 µg/dL, while the high BLL group had levels of 18.12 µg/dL (p < 0.001). Overall, the genetic variants, TC and CC in the VDR FokI were significantly associated with a risk of lead toxicity and the allele "C" was a risk factor (p = 0.00026). Furthermore, the TT genotype of VDR ApaI significantly increased the risk of developing lead poisoning (p = 0.0006). The VDR TaqI SNP was not significantly associated with lead toxicity. The highest BLLs for VDR FokI-CC, VDR ApaI-GG, and VDR TaqI-TT genotypes from High BLL group were 18.42, 15.26, and 18.75 µg/dL, respectively. Older age (51-60 years) was found to be a significant confounding factor for BLLs (p = 0.012). Additional studies in larger sample sizes are needed to firmly establish the role of VDR genotypes and genetic susceptibility to lead poisoning.

Effect of polyethylene glycol surface charge functionalization of SWCNT on the in vitro and in vivo nanotoxicity and biodistribution monitored noninvasively using MRI.

The current study evaluated in vitro and in vivo toxicity of carboxyl or amine polyethylene glycol (PEG) surface functionalization of single-walled carbon nanotubes (SWCNTs). Assessments of cytotoxicity, genotoxicity, immunotoxicity, and oxidative stress were performed in vitro and in vivo (in a 1-month follow-up study). The SWCNT biodistribution was investigated using noninvasive magnetic resonance imaging (MRI). Results confirmed the enhanced biocompatibility of PEG-functionalized SWCNTs compared to non-functionalized materials with significant decreases (p < 0.05) in the percentage of cell viability and increases in ROS generation, mitochondrial membrane potential, cell apoptosis, oxidative stress generation, and oxidative DNA damage in vitro. PEG-functionalized SWCNTs with amine terminals were found to induce prominent increases in ROS generation, mitochondrial membrane potential, and oxidative stress compared to carboxy functionalization. No significant difference in the biodistribution of either functionalized SWCNTs was observed in MRI. In vivo assessments revealed a statistically significant increase (p < 0.05) in oxidative stress as early as 24 h in serum and liver; however, all values normalized at 2 weeks' investigation time point. DNA damage was minimal with either PEG-COOH or PEG-NH2 functionalized SWCNTs after 2 weeks' exposure. The negatively charged SWCNTs caused lesser DNA damage compared to positively charged samples. Carboxy-functionalized SWCNTs did not cause substantial changes in inflammatory mediators and were found to be significantly safer than non-functionalized SWCNTs and may pave the way for novel biomedical applications in cancer diagnosis and therapy.

Blocking Interleukin-4 Receptor α Using Polyethylene Glycol Functionalized Superparamagnetic Iron Oxide Nanocarriers to Inhibit Breast Cancer Cell Proliferation.

PURPOSE: The specific targeting of interleukin-4 receptor α (IL4Rα) receptor offers a promising therapeutic approach for inhibition of tumor cell progression in breast cancer patients. In the current study, the in vitro efficacy of superparamagnetic iron oxide nanoparticles conjugated with anti-IL4Rα blocking antibodies (SPION-IL4Rα) via polyethylene glycol polymers was evaluated in 4T1 breast cancer cells. MATERIALS AND METHODS: Cell viability, reactive oxygen species generation, and apoptosis frequency were assessed in vitro in 4T1 cancer cell lines following exposure to SPION-IL4Rα alone or combined with doxorubicin. In addition, immunofluorescence assessments and fluorimetrywere performed to confirm the specific targeting and interaction of the developed nanocarriers with IL4Rα receptors in breast cancer cells. RESULTS: Blocking of IL4Rα receptors caused a significant decrease in cell viability and induced apoptosis in 4T1 cells. In addition, combined treatment with SPION-IL4Rα+doxorubicin caused significant increases in cell death, apoptosis, and oxidative stress compared to either SPION-IL4Rα or doxorubicin alone, indicating the enhanced therapeutic efficacy of this combination. The decrease in fluorescence intensity upon immunofluorescence and fluorimetry assays combined with increased viability and decreased apoptosis following the blocking of IL4Rα receptors confirmed the successful binding of the synthesized nanocarriers to the target sites on murine 4T1 breast cancerous cells. CONCLUSION: These results suggest that SPION-IL4Rα nanocarriers might be used for successfulreduction of tumor growth and inhibition of progression of metastasis in vivo.

Combination of drug-conjugated SWCNT nanocarriers for efficient therapy of cancer stem cells in a breast cancer animal model.

Targeting breast cancer and more specifically cancer stem cell (CSC) subpopulation, responsible for tumor growth, resistance and self-renewal, using combination of therapeutic drugs selectively delivered via biocompatible nanocarriers, provides a novel approach for effective therapy. Here, we propose to evaluate the potential therapeutic efficacy of combining Paclitaxel and Salinomycin drugs actively targeted to both breast cancer and CSCs in xenograft murine model after conjugation with biocompatible CD44 antibody conjugated SWCNTs via hydrazone linker allowing pH-responsive release mechanism near the acidic tumor microenvironment. Both in vitro investigations on MDA-MB-231, sorted CSC negative or CSC positive fractions and in vivo evaluations on tumor-bearing mice using noninvasive bioluminescence and magnetic resonance imaging confirmed the enhanced therapeutic effect of the combined therapy compared to treatment with individual drug-conjugated nanocarriers or free drug suspensions. Thus, confirmed the great promise of the developed SWCNTs drug delivery system for effective breast cancer treatment by targeting and eradicating both whole tumor cells and CSCs populations.

Specific targeting and noninvasive imaging of breast cancer stem cells using single-walled carbon nanotubes as novel multimodality nanoprobes.

BACKGROUND: The limitation of current breast cancer treatments was elucidated by the presence of cancer stem cells (CSCs) that play essential role in cancer initiation, progression, resistance, recurrence and metastasis. Materials & methods: Biocompatible multimodality single-walled carbon nanotube (SWCNT) nanoprobes were developed. The biodistribution and preferential homing of CD44 antibody-conjugated SWCNTs toward the tumor site were monitored using MRI, single-photon emission computed tomography and near-infrared fluorescence imaging noninvasive imaging modalities. RESULTS: Quantification of SWCNTs by sensitively measuring iron content in sorted CSC populations using inductively coupled plasma-mass spectrometry confirmed the enhanced selective targeting of anti-CD44 SWCNT and immunohistochemistry analyses revealed enhanced colocalization with areas rich in CD44 receptors. DISCUSSION & CONCLUSION: This preclinical study provided encouraging results for efficient targeting of breast CSCs and perspectives for further clinical studies to confirm the efficacy and safety of the designed nanocarriers.

Specific targeting and noninvasive magnetic resonance imaging of an asthma biomarker in the lung using polyethylene glycol functionalized magnetic nanocarriers.

Simultaneous inhibition of IL4 and IL13 via the common receptor chain IL4Rα to block adequately their biologic effects presents a promising therapeutic approach to give the additional relief required for asthma patients. In this study, superparamagnetic iron oxide nanoparticles were conjugated with anti-IL4Rα blocking antibodies via polyethylene glycol (PEG) polymers. The delivery of these blocking antibodies to the inflammatory sites in the lung via the developed nanocarriers was assessed using noninvasive free-breathing pulmonary MRI. Biocompatibility assays confirmed the safety of the developed nanocarriers for pre-clinical investigations. For all the investigated formulations, nanocarriers were found to be very stable at neutral pH. However, the stability noticeably decreased with the PEG length in acidic environment and thus the loaded antibodies were preferentially released. Immunofluorescence and fluorimetry assays confirmed the binding of the nanocarriers to the IL4Rα asthma biomarker. Pulmonary MRI performed using an ultra-short echo time sequence allowed simultaneous noninvasive monitoring of inflammatory responses induced by ovalbumin challenge and tracking of the developed nanocarriers, which were found to colocalize with the inflammatory sites in the lung. Targeting of the developed nanocarriers to areas rich in IL4Rα positive inflammatory cells was confirmed using histological and flow cytometry analyses. The anti-IL4Rα-conjugated nanocarriers developed here have been confirmed to be efficient in targeting key inflammatory cells during chronic lung inflammation following intrapulmonary administration. Targeting efficiency was monitored using noninvasive MRI, allowing detection of the nanocarriers' colocalizations with the inflammatory sites in the lung of ovalbumin-challenged asthmatic mice. Copyright © 2015 John Wiley & Sons, Ltd.

Magnetic Targeting and Delivery of Drug-Loaded SWCNTs Theranostic Nanoprobes to Lung Metastasis in Breast Cancer Animal Model: Noninvasive Monitoring Using Magnetic Resonance Imaging.

PURPOSE: In this study, we aimed to develop novel therapeutic and diagnostic approaches by improving the targeting of doxorubicin-loaded single-walled carbon nanotubes (SWCNTs) to metastatic regions, and monitor their preferential homing and enhanced therapeutic effect using noninvasive free-breathing magnetic resonance imaging (MRI) and bioluminescence imaging. PROCEDURES: High-energy flexible magnets were specifically positioned over the metastatic tumor sites in the lungs. SWCNTs biodistribution, tumor progression, and subsequent treatment efficiency were assessed following administration of the magnetically attracted doxorubicin-loaded anti-CD105 conjugated nanocarriers. RESULTS: The use of high-energy magnets offered improved theranostic effect of doxorubicin-loaded nanocarriers, by magnetically targeting them towards metastatic tumor sites in the lungs. MRI allowed sensitive monitoring of nanocarriers biodistribution in the abdominal organs, their preferential homing towards the metastatic sites, and their enhanced therapeutic effect. CONCLUSIONS: Combination of noninvasive MRI to localize sensitively the tumor sites, with specific positioning of magnets that can enhance the magnetic targeting of nanocarriers, allowed increasing the treatment efficiency.

Effect of surface coating on the biocompatibility and in vivo MRI detection of iron oxide nanoparticles after intrapulmonary administration.

Superparamagnetic iron oxide nanoparticles (SPIONs) have attracted special attention as novel nanoprobes capable of improving both the therapy and diagnosis of lung diseases. For safe prospective clinical applications, their biocompatibility has to be assessed after intrapulmonary administration. This study was therefore conducted to understand the biological impact of SPIONs and their further surface-functionalization with polyethylene glycol (PEG) having either negative (i.e. carboxyl) or positive (i.e. amine) terminal in a 1-month longitudinal study following acute and sub-acute exposures. Noninvasive free-breathing MR imaging protocols were first optimized to validate SPIONs detection in the lung and investigate possible subsequent systemic translocation to abdominal organs. Pulmonary Magnetic Resonance Imaging (MRI) allowed successful in vivo detection of SPIONs in the lung using ultra-short echo time sequence. Following high-dose lung administration, MR imaging performed on abdominal organs detected transient accumulation of SPIONs in the liver. Iron quantification using Inductive coupled plasma - Mass mass spectroscopy (ICP-MS) confirmed MRI readouts. Oxidative stress induction and genotoxicity were then conducted to evaluate the biocompatibility of SPIONs with their different formulations in a mouse model. A significant increase in lipid peroxidation was observed in both acute and sub-acute sets and found to regress in a time-dependent manner. PEG functionalized SPIONs revealed a lower effect with no difference between both terminal modifications. Genotoxicity assessments revealed an increase in DNA damage and gene expression of CCL-17 and IL-10 biomarkers following SPIONs administration, which was significantly higher than surface-modified nanoparticles and decreased in a time-dependent manner. However, SPIONs with carboxyl terminal showed a slightly prominent effect compared to amine modification.

Intrapulmonary administration of bone-marrow derived M1/M2 macrophages to enhance the resolution of LPS-induced lung inflammation: noninvasive monitoring using free-breathing MR and CT imaging protocols.

BACKGROUND: Alveolar macrophages, with their high functional plasticity, were reported to orchestrate the induction and resolution of inflammatory processes in chronic pulmonary diseases. Noninvasive imaging modalities that offer simultaneous monitoring of inflammation progression and tracking of macrophages subpopulations involved in the inflammatory cascade, can provide an ideal and specific diagnostic tool to visualize the action mechanism in its initial stages. Therefore, the purpose of the current study was to evaluate the role of M1 and M2 macrophages in the resolution of lipopolysaccharide (LPS)-induced lung inflammation and monitor this process using noninvasive free-breathing MRI and CT protocols. METHODS: Bone-marrow derived macrophages were first polarized to M1 and M2 macrophages and then labeled with superparamagnetic iron oxide nanoparticles. BALB/c mice with lung inflammation received an intrapulmonary instillation of these ex vivo polarized M1 or M2 macrophages. The biodistribution of macrophages subpopulations and the subsequent resolution of lung inflammation were noninvasively monitored using MRI and micro-CT. Confirmatory immunohistochemistry analyses were performed on lung tissue sections using specific macrophage markers. RESULTS: As expected, large inflammatory areas noninvasively imaged using pulmonary MR and micro-CT were observed within the lungs following LPS challenge. Subsequent intrapulmonary administration of M1 and M2 macrophages resulted in a significant decrease in inflammation starting from 72 h. Confirmatory immunohistochemistry analyses established a progression of lung inflammation with LPS and its subsequent reduction with both macrophages subsets. An enhanced resolution of inflammation was observed with M2 macrophages compared to M1. CONCLUSIONS: The current study demonstrated that ex vivo polarized macrophages decreased LPS-induced lung inflammation. Noninvasive free-breathing MR and CT imaging protocols enabled efficient monitoring of progression and resolution of lung inflammation.

Preferential magnetic targeting of carbon nanotubes to cancer sites: noninvasive tracking using MRI in a murine breast cancer model.

AIM: This study evaluated the improvement in magnetic targeting of single-walled carbon nanotubes (SWCNTs) in a 4T1-induced breast cancer murine model and compared their enhanced delivery with active targeted SWCNTs conjugated with a specific antibody for prospective applications as drug-delivery nanocarriers. MATERIALS & METHODS: Polyvinylpyrrolidone SWCNTs, loaded with iron oxide nanoparticles to improve their magnetic resonance detection and magnet attraction using an optimized flexible magnet positioned over the tumor site were developed. They were equally conjugated with Endoglin/CD105 antibody for SWCNTs active targeting. A noninvasive MRI protocol was then optimized to allow in vivo imaging of tumor site, sensitive detection of SWCNTs and apparent diffusion coefficient measurements. Special focus was devoted to evaluate the biocompatibility of the used SWCNTs. RESULTS: Iron-tagged SWCNTs exhibited very high magnetic resonance r2* relaxivities allowing their sensitive detection using noninvasive MRI and enhanced targeting using the magnet. Biocompatibility evaluations confirmed their safety for animal administration. Both T2* and apparent diffusion coefficient measurements confirmed their enhanced magnetic targeting starting from 2 h postinjection while a lower, but statistically significant enhanced targeting of antibody-conjugated active targeting was observed starting from 24 h postinjection of iron-tagged SWCNT + CD105 samples. CONCLUSION: These results demonstrate the efficiency of magnetic targeting to specifically deliver higher load of iron-tagged SWCNTs as novel nanocarriers for cancer theranostics and allow their sensitive detection using noninvasive MRI.

Magnetic single-walled carbon nanotubes as efficient drug delivery nanocarriers in breast cancer murine model: noninvasive monitoring using diffusion-weighted magnetic resonance imaging as sensitive imaging biomarker.

PURPOSE: Targeting doxorubicin (DOX) by means of single-walled carbon nanotube (SWCNT) nanocarriers may help improve the clinical utility of this highly active therapeutic agent. Active targeting of SWCNTs using tumor-specific antibody and magnetic attraction by tagging the nanotubes with iron oxide nanoparticles can potentially reduce the unnecessary side effects and provide enhanced theranostics. In the current study, the in vitro and in vivo efficacy of DOX-loaded SWCNTs as theranostic nanoprobes was evaluated in a murine breast cancer model. METHODS: Iron-tagged SWCNTs conjugated with Endoglin/CD105 antibody with or without DOX were synthetized and extensively characterized. Their biocompatibility was assessed in vitro in luciferase (Luc2)-expressing 4T1 (4T1-Luc2) murine breast cancer cells using TiterTACS™ Colorimetric Apoptosis Detection Kit (apoptosis induction), poly (ADP-ribose) polymerase (marker for DNA damage), and thiobarbituric acid-reactive substances (oxidative stress generation) assays, and the efficacy of DOX-loaded SWCNTs was evaluated by measuring the radiance efficiency using bioluminescence imaging (BLI). Tumor progression and growth were monitored after 4T1-Luc2 cells inoculation using noninvasive BLI and magnetic resonance imaging (MRI) before and after subsequent injection of SWCNT complexes actively and magnetically targeted to tumor sites. RESULTS: Significant increases in apoptosis, DNA damage, and oxidative stress were induced by DOX-loaded SWCNTs. In addition, a tremendous decrease in bioluminescence was observed in a dose- and time-dependent manner. Noninvasive BLI and MRI revealed successful tumor growth and subsequent attenuation along with metastasis inhibition following DOX-loaded SWCNTs injection. Magnetic tagging of SWCNTs was found to produce significant discrepancies in apparent diffusion coefficient values providing a higher contrast to detect treatment-induced variations as noninvasive imaging biomarker. In addition, it allowed their sensitive noninvasive diagnosis using susceptibility-weighted MRI and their magnetic targeting using an externally applied magnet. CONCLUSION: Enhanced therapeutic efficacy of DOX delivered through antibody-conjugated magnetic SWCNTs was achieved. Further, the superiority of apparent diffusion coefficient measurements using diffusion-weighted MRI was found to be a sensitive imaging biomarker for assessment of treatment-induced changes.

MR imaging and targeting of a specific alveolar macrophage subpopulation in LPS-induced COPD animal model using antibody-conjugated magnetic nanoparticles.

PURPOSE: Targeting and noninvasive imaging of a specific alveolar macrophage subpopulation in the lung has revealed the importance for early and better diagnosis and therapy of chronic obstructive pulmonary disease (COPD). In this study, the in vivo effect of pulmonary administration of iron oxide nanoparticles on the polarization profile of macrophages was assessed, and a noninvasive free-breathing magnetic resonance imaging (MRI) protocol coupled with the use of biocompatible antibody-conjugated superparamagnetic iron oxide (SPIO) nanoparticles was developed to enable specific targeting and imaging of a particular macrophage subpopulation in lipopolysaccharide-induced COPD mice model. MATERIALS AND METHODS: Enzyme-linked immunosorbent assay, Real-time polymerase chain reaction, and flow cytometry analysis were performed to assess the biocompatibility of PEGylated dextran-coated SPIO nanoparticles. Specific biomarkers for M1 and M2 macrophages subsets were selected for conjugation with magnetic nanoparticles. MRI protocol using ultra-short echo time sequence was optimized to enable simultaneous detection of inflammation progress in the lung and detection of macrophages subsets. Flow cytometry and immunohistochemistry analysis were finally performed to confirm MRI readouts and to characterize the polarization profile of targeted macrophages. RESULTS: The tested SPIO nanoparticles, under the current experimental conditions, were found to be biocompatible for lung administration in preclinical settings. Cluster of differentiation (CD)86- and CD206-conjugated magnetic nanoparticles enabled successful noninvasive detection of M1 and M2 macrophage subpopulations, respectively, and were found to co-localize with inflammatory regions induced by lipopolysaccharide challenge. No variation in the polarization profile of targeted macrophages was observed, even though a continuum switch in their polarization might occur. However, further confirmatory studies are required to conclusively establish this observation. CONCLUSION: Coupling of magnetic iron oxide nanoparticles with a specific antibody targeted to a particular macrophage subpopulation could offer a promising strategy for an early and better diagnosis of pulmonary inflammatory diseases using noninvasive MRI.