PURPOSE:To compare diagnostic reliability between an intravoxel incoherent motion (IVIM) imaging and an arterial spin labeling (ASL) in assessment of renal blood flow in rodents. METHODS:We first evaluated 3 different fitting methods on 5 datasets of diffusion-weighted imaging (DWI) with 10 b-values (0-1000 s/mm2) for bi-exponential analysis in IVIM imaging to calculate pseudo-diffusion parameters. Coefficient of variation (CV) for each parameter and correlation among the parameters was assessed to test the robustness of the 3 fitting methods. Subsequently, DWI and ASL methods were performed before and 14 days after onset of acute kidney injury (AKI) in a rat model. Temporal change before and after AKI onset in the pseudo-diffusion parameters in 3 fitting methods was compared with that in the renal blood flow (RBF) derived in the ASL method. RESULTS:The CVs in all IVIM parameters were the lowest in the fitting method that estimated pseudo-diffusion parameters after a fixed true-diffusion was determined where the pseudo- and true-diffusion coefficients had no correlation. The RBF substantially reduced (~50%, P < 0.001) due to the AKI onset; however, no pseudo-diffusion parameters in any of 3 fitting methods could not detect the change. Further, any pseudo-diffusion parameters showed no correlation with the RBF. CONCLUSION:Pseudo-diffusion parameters in the IVIM concept were not reliable to estimate RBF in the study. Since the kidney has a unique profile in the "tissue flow", our data indicate that study design and interpretation of results needs to be carefully considered when IVIM imaging is used for evaluation of blood flow in tissue, especially in the kidney.

Cardiovascular disease (CVD) is the major cause of death in chronic kidney disease (CKD) and is associated with high circulating fibroblast growth factor (FGF)23 levels. It is unresolved whether high circulating FGF23 is a mere biomarker or pathogenically contributes to cardiomyopathy. It is also unknown whether the C-terminal FGF23 peptide (cFGF23), a natural FGF23 antagonist proteolyzed from intact FGF23 (iFGF23), retards CKD progression and improves cardiomyopathy. We addressed these questions in three murine models with high endogenous FGF23 and cardiomyopathy. First, we examined wild-type (WT) mice with CKD induced by unilateral ischemia-reperfusion and contralateral nephrectomy followed by a high-phosphate diet. These mice were continuously treated with intraperitoneal implanted osmotic minipumps containing either iFGF23 protein to further escalate FGF23 bioactivity, cFGF23 peptide to block FGF23 signaling, vehicle, or scrambled peptide as negative controls. Exogenous iFGF23 protein given to CKD mice exacerbated pathological cardiac remodeling and CKD progression, whereas cFGF23 treatment improved heart and kidney function, attenuated fibrosis, and increased circulating soluble Klotho. WT mice without renal insult placed on a high-phosphate diet and homozygous Klotho hypomorphic mice, both of whom develop moderate CKD and clear cardiomyopathy, were treated with cFGF23 or vehicle. Mice treated with cFGF23 in both models had improved heart and kidney function and histopathology. Taken together, these data indicate high endogenous iFGF23 is not just a mere biomarker but pathogenically deleterious in CKD and cardiomyopathy. Furthermore, attenuation of FGF23 bioactivity by cFGF23 peptide is a promising therapeutic strategy to protect the kidney and heart from high FGF23 activity.NEW & NOTEWORTHY There is a strong correlation between cardiovascular morbidity and high circulating fibroblast growth factor 23 (FGF23) levels, but causality was never proven. We used a murine chronic kidney disease (CKD) model to show that intact FGF23 (iFGF23) is pathogenic and contributes to both CKD progression and cardiomyopathy. Blockade of FGF23 signaling with a natural proteolytic product of iFGF23, C-terminal FGF23, alleviated kidney and cardiac histology, and function in three separate murine models of high endogenous FGF23.

Aim: The aim of this study was to assess the utility of weighted amide proton transfer (APTw) MRI in three different rodent models of hepatocellular carcinoma (HCC).Methods: APTw MRI was evaluated in models of diethylnitrosamine (DEN) induced HCC, N1S1 syngeneic orthotopic xenograft and human HepG2 ectopic xenograft.Results: All models of HCC showed a higher APTw signal over the surrounding normal tissues. In the DEN model, the APTw signal could differentiate HCC lesions from benign nodules. Intra-arterial administration of low-density lipoprotein docosahexaenoic acid (LDL-DHA) nanoparticles to N1S1 xenografts rapidly lowered the tumor APTw signal within 72 h. Direct injections of LDL-DHA nanoparticles into HepG2 xenografts also showed similar therapeutic responses.Conclusion: We have demonstrated the utility of APTw imaging in the diagnostic/therapeutic management of HCC.

Disparities in cancer patient responses have prompted widespread searches to identify differences in sensitive vs. nonsensitive populations and form the basis of personalized medicine. This customized approach is dependent upon the development of pathway-specific therapeutics in conjunction with biomarkers that predict patient responses. Here, we show that Cdk5 drives growth in subgroups of patients with multiple types of neuroendocrine neoplasms. Phosphoproteomics and high throughput screening identified phosphorylation sites downstream of Cdk5. These phosphorylation events serve as biomarkers and effectively pinpoint Cdk5-driven tumors. Toward achieving targeted therapy, we demonstrate that mouse models of neuroendocrine cancer are responsive to selective Cdk5 inhibitors and biomimetic nanoparticles are effective vehicles for enhanced tumor targeting and reduction of drug toxicity. Finally, we show that biomarkers of Cdk5-dependent tumors effectively predict response to anti-Cdk5 therapy in patient-derived xenografts. Thus, a phosphoprotein-based diagnostic assay combined with Cdk5-targeted therapy is a rational treatment approach for neuroendocrine malignancies.

Theranostic systems capable of delivering imaging and therapeutic agents at a specific target are the focus of intense research efforts in drug delivery. To overcome non-degradability and toxicity concerns of conventional theranostic systems, we formulated a novel thermo-responsive fluorescent polymer (TFP) and conjugated it on the surface of iron oxide magnetic nanoparticles (MNPs) for imaging and therapeutic applications in solid tumors. Methods: TFP-MNPs were synthesized by copolymerizing poly(N-isopropylacrylamide), allylamine and a biodegradable photoluminescent polymer, and conjugating it on MNPs via a free radical polymerization reaction. Physicochemical properties of the nanoparticles were characterized using Fourier transform infrared spectroscopy, dynamic light scattering, and vibrational sample magnetometry. Nanoparticle cytocompatibility, cellular uptake and cytotoxicity were evaluated using in vitro cell assays. Finally, in vivo imaging and therapeutic efficacy studies were performed in subcutaneous tumor xenograft mouse models. Results: TFP-MNPs of ~135 nm diameter and -31 mV ζ potential maintained colloidal stability and superparamagnetic properties. The TFP shell was thermo-responsive, fluorescent, degradable, and released doxorubicin in response to temperature changes. In vitro cell studies showed that TFP-MNPs were compatible to human dermal fibroblasts and prostate epithelial cells. These nanoparticles were also taken up by prostate and skin cancer cells in a dose-dependent manner and exhibited enhanced killing of tumor cells at 41°C. Preliminary in vivo studies showed theranostic capabilities of the nanoparticles with bright fluorescence, MRI signal, and therapeutic efficacy under magnetic targeting after systemic administration in tumor bearing mice. Conclusion: These results indicate the potential of TFP-MNPs as multifunctional theranostic nanoparticles for various biological applications, including solid cancer management.

Mildly elevated serum uric acid levels are common in people with metabolic syndrome and type 2 diabetes mellitus (T2DM), but whether elevated uric acid has a causal role in the pathogenesis of diabetes remains uncertain. We tested whether chronic mild hyperuricemia in rodents under controlled laboratory conditions can cause glucose intolerance in otherwise healthy animals, or whether it can worsen glucometabolic control in animals that are genetically predisposed to T2DM. We used an established model of experimental hyperuricemia in rodents with potassium oxonate dietary supplementation, which led to sustained, approximately two-fold elevation of uric acid compared with control animals. We also reversed the hyperuricemic effect of oxonate in some animals by treatment with a xanthine oxidase inhibitor. Manipulation of serum uric acid levels in Sprague-Dawley rats for up to 18 weeks did not affect fasting glucose and glucose tolerance. Blood pressure was also not affected by hyperuricemia in rats fed a Western-type diet. We next sought to determine whether uric acid may aggravate or accelerate the onset of glucometabolic abnormalities in rats already predisposed to T2DM. Chronic oxonate treatment in Zucker diabetic fatty (ZDF) and lean control rats for up to 6 weeks did not affect fasting glucose, insulin, and glucose tolerance in ZDF rats. Taken together, these findings indicate that elevated uric acid does not directly contribute to the pathogenesis of glucose intolerance and T2DM in rodents.

Medullary thyroid carcinoma (MTC) is a slow growing neuroendocrine (NE) tumor for which few treatment options are available. Its incidence is rising and mortality rates have remained unchanged for decades. Increasing the repertoire of available treatments is thus crucial to manage MTC progression. Scarcity of patient samples and of relevant animal models are two challenges that have limited the development of effective non-surgical treatments. Here we use a clinically accurate mouse model of MTC to assess the effects and mode of action of the tyrosine kinase inhibitor (TKI) Vandetanib, one of only two drugs currently available to treat MTC. Effects on tumor progression, histopathology, and tumorigenic signaling were evaluated. Vandetanib blocked MTC growth through an anti-angiogenic mechanism. Furthermore, Vandetanib had an apparent anti-angiogenic effect in a patient MTC sample. Vandetanib displayed minimal anti-proliferative effects in vivo and in human and mouse MTC tumor-derived cells. Based on these results, we evaluated the second-generation TKI, Nintedanib, alone and in combination with the histone deacetylase (HDAC) inhibitor, Romidepsin, as potential alternative treatments to Vandetanib. Nintedanib showed an anti-angiogenic effect while Romidepsin decreased proliferation. Mechanistically, TKIs attenuated RET-, VEGFR2- and PI3K/AKT/FOXO signaling cascades. Nintedanib alone or in combination with Romidepsin, but not Vandetanib, inhibited mTOR signaling suggesting Nintedanib may have broader anti-cancer applicability. These findings validate the MTC mouse model as a clinically relevant platform for preclinical drug testing and reveal the modes of action and limitations of TKI therapies.

Chemical exchange saturation transfer (CEST) imaging has been demonstrated to discuss the concentration changes of amide proton, glutamate, creatine, or glucose measured at 3.5, 3.0, 2.0, and 1.0-1.2 ppm. However, these peaks in z-spectra are quite broad and overlap with each other, and thus, the independence of a CEST signal on any specific metabolite is still open to question. Here, we described whether there was interference among the CEST signals and how these CEST signals behave when the power of the presaturation pulse was changed. Based on these results, further experiments were designed to investigate a method to increase the independence of the CEST signal in both phantoms and animals. The result illustrates a clear interference among CEST signals. A presaturation power adjusted pulsed-(PPAP-) CEST method which was designed based on the exchange rates of the metabolites can be used to remove contributions from other exchanging species in the same sample. Further, the method was shown to improve the independence of the glutamate signal in vivo in the renal medulla in mice. The PPAP-CEST method has the potential to increase the independence of any target CEST signals in vivo by choosing the appropriate combination of pulse amplitudes and durations.

Although aberrant EGFR signaling is widespread in cancer, EGFR inhibition is effective only in a subset of non-small cell lung cancer (NSCLC) with EGFR activating mutations. A majority of NSCLCs express EGFR wild type (EGFRwt) and do not respond to EGFR inhibition. TNF is a major mediator of inflammation-induced cancer. We find that a rapid increase in TNF level is a universal adaptive response to EGFR inhibition in NSCLC, regardless of EGFR status. EGFR signaling actively suppresses TNF mRNA levels by inducing expression of miR-21, resulting in decreased TNF mRNA stability. Conversely, EGFR inhibition results in loss of miR-21 and increased TNF mRNA stability. In addition, TNF-induced NF-κB activation leads to increased TNF transcription in a feed-forward loop. Inhibition of TNF signaling renders EGFRwt-expressing NSCLC cell lines and an EGFRwt patient-derived xenograft (PDX) model highly sensitive to EGFR inhibition. In EGFR-mutant oncogene-addicted cells, blocking TNF enhances the effectiveness of EGFR inhibition. EGFR plus TNF inhibition is also effective in NSCLC with acquired resistance to EGFR inhibition. We suggest concomitant EGFR and TNF inhibition as a potentially new treatment approach that could be beneficial for a majority of lung cancer patients.

The aim of this study is to fabricate a hybrid composite of iron (Fe) core–carbon (C) shell nanoparticles with enhanced magnetic properties for contrast enhancement in magnetic resonance imaging (MRI). These new classes of magnetic core–shell nanoparticles are synthesized using a one-step top–down approach through the electric plasma discharge generated in the cavitation field in organic solvents by an ultrasonic horn. Transmission electron microscopy (TEM) observations revealed the core–shell nanoparticles with 10–85 nm in diameter with excellent dispersibility in water without any agglomeration. TEM showed the structural confirmation of Fe nanoparticles with body centered cubic (bcc) crystal structure. Magnetic multi-functional hybrid composites of Fe core–C shell nanoparticles were then evaluated as negative MRI contrast agents, displaying remarkably high transverse relaxivity (r2) of 70 mM−1·S−1 at 7 T. This simple one-step synthesis procedure is highly versatile and produces desired nanoparticles with high efficacy as MRI contrast agents and potential utility in other biomedical applications.

To investigate whether amide proton transfer (APT) MR imaging can differentiate high-grade gliomas (HGGs) from low-grade gliomas (LGGs) among gliomas without intense contrast enhancement (CE).

alpha-Klotho is highly expressed in the kidney, and its extracellular domain is cleaved and released into the circulation. Chronic kidney disease (CKD) is a state of alpha-Klotho deficiency, which exerts multiple negative systemic effects on numerous organs including the cardiovascular system. Since acute kidney injury (AKI) greatly escalates the risk of CKD development, we explored the effect of alpha-Klotho on prevention and treatment on post-AKI to CKD progression and cardiovascular disease. Therein, ischemia reperfusion injury-induced AKI was followed by early administration of recombinant alpha-Klotho or vehicle starting one day and continued for four days after kidney injury (CKD prevention protocol). A CKD model was generated by unilateral nephrectomy plus contralateral ischemia reperfusion injury. Late administration of alpha-Klotho in this model was started four weeks after injury and sustained for 12 weeks (CKD treatment protocol). The prevention protocol precluded AKI to CKD progression and protected the heart from cardiac remodeling in the post-AKI model. One important effect of exogenous alpha-Klotho therapy was the restoration of endogenous alpha-Klotho levels long after the cessation of exogenous alpha-Klotho therapy. The treatment protocol still effectively improved renal function and attenuated cardiac remodeling in CKD, although these parameters did not completely return to normal. In addition, alpha-Klotho administration also attenuated high phosphate diet induced renal and cardiac fibrosis, and improved renal and cardiac function in the absence of pre-existing renal disease. Thus, recombinant alpha-Klotho protein is safe and efficacious, and might be a promising prophylactic or therapeutic option for prevention or retardation of AKI-to-CKD progression and uremic cardiomyopathy.

Late-stage diagnosis of lung cancer occurs ~95% of the time due to late manifestation of its symptoms, necessitating rigorous treatment following diagnosis. Existing treatment methods are limited by lack of specificity, systemic toxicity, temporary remission, and radio-resistance in lung cancer cells. In this research, we have developed a folate receptor-targeting multifunctional dual drug-loaded nanoparticle (MDNP) containing a poly(N-isopropylacrylamide)-carboxymethyl chitosan shell and poly lactic-co-glycolic acid (PLGA) core for enhancing localized chemo-radiotherapy to effectively treat lung cancers. The formulation provided controlled releases of the encapsulated therapeutic compounds, NU7441 - a potent radiosensitizer, and gemcitabine - an FDA approved chemotherapeutic drug for lung cancer chemo-radiotherapy. The MDNPs showed biphasic NU7441 release and pH-dependent release of gemcitabine. These nanoparticles also demonstrated good stability, excellent hemocompatibility, outstanding in vitro cytocompatibility with alveolar Type I cells, and dose-dependent caveolae-mediated in vitro uptake by lung cancer cells. In addition, they could be encapsulated with superparamagnetic iron oxide (SPIO) nanoparticles and visualized by MRI in vivo . Preliminary in vivo results demonstrated the low toxicity of these particles and their use in chemo-radiotherapy to effectively reduce lung tumors. These results indicate that MDNPs can potentially be used as nano-vehicles to provide simultaneous chemotherapy and radiation sensitization for lung cancer treatment.

Background: Medullary thyroid carcinoma (MTC) originates from the thyroid gland parafollicular cells. Treatment options for progressive, metastatic MTC patients are limited to the recently FDA-approved tyrosine kinase inhibitors (TKIs), Vandetanib and Cabozantinib, which target multiple receptor tyrosine kinases, including VEGFR2. However, the efficacy of TKIs is limited and development of TKI resistance is common. Here we examined, the effect of a combinatorial drug therapy using the TKI, Nintedanib, and the histone deacetylase (HDAC) inhibitor, Romidepsin, on MTC growth and mouse survival.

To characterize the 3-dimensional (3D) geometric shape and surface characteristics of multiple sclerosis (MS) lesions in contrast to non-specific white matter (NSWM) findings.

BACKGROUND AND PURPOSEThere remains a need to further refine the ability of clinicians to differentiate multiple sclerosis (MS) from other disease etiologies. Here, we illustrate the value of 3-dimensional (3D) geometric shape and surface lesion characteristics between disease states. METHODSStandardized 3-Tesla 3D brain magnetic resonance imaging studies were performed on enrolled MS and nonspecific white matter (NSWM) patients. Focal supratentorial lesions were identified, reconstructed using maximum intensity projection, manually segmented, and 3D printed. Printed 3D models were randomly evaluated by three blinded raters for selected shape and surface characteristics. Regression models adjusting for age, disease duration, and individual patient effects were applied to assess lesion characteristics between patient groups. Patient-level and latent class analyses between groups were performed. RESULTSA total of 1,001 supratentorial lesions were analyzed (710 MS; 291 NSWM) from 30 patients (19 with confirmed MS [11 female; median age = 33.6 years, range: 26.9-54.5], median disease duration = 2.2 years [.4-19.4]), 11 with verified nonspecific white matter (NSWM) disease without MS (11 female; median age = 55.0 years, range: 27.9-66.2). Lesions originating from MS in comparison to NSWM patients demonstrated a higher percentage of asymmetry (75.9% vs. 43%; OR: 4.39 [2.37-8.12]; P < .001), complex surface morphologies (65.9% vs. 27.8%; OR: 2.3 [1.74-3.05]; P < .001), and were multilobular (11.0% vs. .3%, P < .001), and elongated (12.8% vs. 2.4%, P < .001) in shape. Spatially, these traits were of higher frequency within the juxtacortical, deep white matter, and periventricular regions. CONCLUSIONThree-dimensional lesion data may provide new biologic insights related to injury along with offering another approach for determining the origin of lesion types.

In this study, we evaluated the dependence of saturation pulse length on APT imaging of diffuse gliomas using a parallel transmission-based technique. Twenty-two patients with diffuse gliomas (9 low-grade gliomas, LGGs, and 13 high-grade gliomas, HGGs) were included in the study. APT imaging was conducted at 3T with a 2-channel parallel transmission scheme using three different saturation pulse lengths (0.5 s, 1.0 s, 2.0 s). The 2D fast spin-echo sequence was used for imaging. Z-spectrum was obtained at 25 frequency offsets from -6 to +6 ppm (step 0.5 ppm). A point-by-point B0 correction was performed with a B0 map. Magnetization transfer ratio (MTRasym) and ΔMTRasym (contrast between tumor and normal white matter) at 3.5 ppm were compared among different saturation lengths. A significant increase in MTRasym (3.5 ppm) of HGG was found when the length of saturation pulse became longer (3.09 ± 0.54% at 0.5 s, 3.83 ± 0.67% at 1 s, 4.12 ± 0.97% at 2 s), but MTRasym (3.5 ppm) was not different among the saturation lengths in LGG. ΔMTRasym (3.5 ppm) increased with the length of saturation pulse in both LGG (0.48 ± 0.56% at 0.5 s, 1.28 ± 0.56% at 1 s, 1.88 ± 0.56% at 2 s and HGG (1.72 ± 0.54% at 0.5 s, 2.90 ± 0.49% at 1 s, 3.83 ± 0.88% at 2 s). In both LGG and HGG, APT-weighted contrast was enhanced with the use of longer saturation pulses.

This article reports the development of biodegradable photoluminescent polymer (BPLP)-based nanoparticles (NPs) incorporating either magnetic nanoparticles (BPLP-MNPs) or gadopentate dimeglumine (BPLP-Gd NPs), for cancer diagnosis and treatment. The aim of the study is to compare these nanoparticles in terms of their surface properties, fluorescence intensities, MR imaging capabilities, and in vitro characteristics to choose the most promising dual-imaging nanoprobe. Results indicate that BPLP-MNPs and BPLP-Gd NPs had a size of 195 +/- 43 nm and 161 +/- 55 nm, respectively and showed good stability in DI water and 10% serum for 5 days. BPLP-Gd NPs showed similar fluorescence as the original BPLP materials under UV light, whereas BPLP-MNPs showed comparatively less fluorescence. VSM and MRI confirmed that the NPs retained their magnetic properties following encapsulation within BPLP. Further, in vitro studies using HPV-7 immortalized prostate epithelial cells and human dermal fibroblasts (HDFs) showed > 70% cell viability up to 100 mu g/ml NP concentration. Dose-dependent uptake of both types of NPs by PC3 and LNCaP prostate cancer cells was also observed. Thus, our results indicate that BPLP-Gd NPs would be more appropriate for use as a dual-imaging probe as the contrast agent does not mask the fluorescence of the polymer. Future studies would involve in vivo imaging following administration of BPLP-Gd NPs for biomedical applications including cancer detection.