Delayed identification and diagnosis of Huntington\u27s disease due to psychiatric symptoms

Huntington\u27s disease (HD) is a progressive neurodegenerative illness that affects 2-9/100.000 of the general population. The usual onset is at around age 35-40 years, but there were cases with onset above 55 years. The disease manifests clinically with many neurological and psychiatric symptoms, leading in advanced phases to dementia, but cognitive symptoms are frequently present much earlier in the disease course. HD is caused by an expanded polyglutamine stretch in the N-terminal part of a 350 kDa protein called huntingtin (HTT). This stretch is encoded by a trinucleotide CAG repetition in exon 1 of HTT. An expansion of greater than 36 repeats results in HD. The number of repeats is inversely correlated with the age of onset of motor symptoms, and disease onset during childhood or adolescence is associated with more than 60 CAG repeats. Mood disturbances may be one of the earliest symptoms of HD and may precede the onset of the motor pheno-type for almost 10 years. Neuropsychiatric symptoms may delay the appropriate diagnosis of HD and have major implications for disease management, prognosis and quality of life for patients and families. This case study is about a 58 years old female patient with late identification of Huntington\u27s disease after two admissions to psychiatric inpatient units, for the treatment of behavioral disturbances

Development of a robust protocol for vulnerable plaque characterization by using two peptide-functionalized USPIO derivaties

Purpose: Rupture of atherosclerotic plaque is the primary cause of sudden cardiac death mainly in the industrialized countries. The term 'plaque rupture' defines a structural defect in the fibrous cap that separates a necrotic core from the lumen resulting in its exposure to the blood via a gap in the cap (Schwartz SM et al, Arterioscler Thromb Vasc Biol, 2007, 27, 705). In most patients, acute ischemic events are caused by the disruption of type IV and Va lipid-rich lesions, which are often not angiographically visible (Frank H, Am Heart J, 2001, 141, S45). ApoE-KO mouse model of atherosclerosis is characterized, in certain circumstances, by human-like plaque rupture events (Johnson JL & Jackson CL, Atherosclerosis, 2001, 154, 399). VCAM-1 and apoptotic cell-targeted peptides identified and validated during our previous work (Burtea C et al, J Med Chem, 2009, 52, 4725; Burtea C et al, Mol Pharm, 2009, 6, 1903) were now conjugated to USPIO (USPIO-R832 for VCAM-1 targeting; USPIO-R826 for apoptosis targeting) and assessed by MRI on ApoE-KO mice. The results were then correlated with several biomarkers of plaque vulnerability which were evaluated by immunohistochemistry. Materials and Methods: Female ApoE-KO mice injected with 100 µmol Fe/kg were imaged on a 4.7 T Bruker MRI at the level of abdominal aorta with RARE (TR/TE = 3000/20 ms, spatial resolution = 90 µm) and FLASH (TR/TE = 175/1.88 ms, flip angle = 90°, spatial resolution = 172 µm) imaging protocols. After MRI investigations, aortic samples were examined by histochemistry for the binding of contrast agent (Perl's staining protocol), the presence of collagen and thrombus (Masson's trichrome staining), of angiogenic blood vessels (VCAM-1 and PECAM-1 staining), apoptotic cells (caspase-3), macrophages (Mac 1), cholesterol (Sudan IV), and smooth muscle cells (?-actin staining). The MR images and histological pictures were then analyzed with ImageJ software. Results: Both USPIO-R832 and USPIO-R826 produced a maximum negative contrast 30 min after administration (Fig. 1), being constant until the end of MRI studies (90 min). The plaque surface was measured on images and it was correlated to the level of plaque enhancement and to the histological observations. USPIO-R826 has mainly enhanced lipid-rich plaques, while this parameter did not seem to influence the binding of USPIO-R832 which enhanced fibrous plaques as well. Conclusion: Our VCAM-1 and apoptotic cell targeted USPIO derivatives seem to be highly promising tools for atherosclerosis imaging contributing to the detection of vulnerable plaques. They are able to attain their target in low doses and as fast as 30 min after administration

Development and validation of a peptide-vectorized superparamagnetic imaging probe designed for detection of inflammation in atherosclerotic plaque

Introduction Atherosclerosis develops in response to vascular injury and involves inflammation and vessel remodeling. VCAM-1 is an important biomarker of various inflammatory disorders having a particular relevance for the pathological process of atherosclerotic disease. Molecularly targeted imaging probes have gained great popularity during the last decade in the context of theranostic strategies. The imaging of VCAM-1 expression has thus been approached with antibodies or peptides conjugated to nuclear, magnetooptical, or ultrasound probes. However, the size of most atherosclerotic lesions is below the spatial resolution of nuclear or ultrasound imaging systems. MRI is the only clinical imaging technique able to attain a spatial resolution in the order of micrometers. Nevertheless, the low sensitivity achieved with magnetic probes constitutes a real challenge for molecular targeting by MRI. Owing to their large NMR efficacy, iron oxide nanoparticles may represent an attractive probe alternative [1, 2]. During our previous work [3], we have identified and validated a VCAM-1-targeted cyclic heptapeptide which was able to detect specifically this adhesion molecule both in a mouse a model of T cell mediated hepatitis, and in atherosclerotic plaque of ApoE-KO mice. In the present work, this peptide was conjugated to USPIO (USPIO-R832), and VCAM-1 binding was first confirmed on HUVEC stimulated with TNF-alpha. Subsequently, USPIO-R832 was evaluated by MRI at 4.7T on ApoE-KO mice, by using T2 and T2*-weighted imaging sequences. The ability to bind to atherosclerotic plaque of this molecular imaging probe was furthermore corroborated by histochemistry. The control imaging probe was represented by USPIO vectorized by a non-specific peptide (USPIO-NSP). Materials and methods The peptides were conjugated to USPIO as previously described [4]. The size of functionalized USPIO was of ~30 nm, while their r2 at 60 MHz and 37°C was of 86 s-1 mM-1 for USPIO-R832 and of 90 s-1 mM-1 for USPIO-NSP. Female C57Bl ApoEtm1unc mice received a Western diet (0.21% cholesterol) for 3 months prior to the MRI studies. The contrast agents were assessed blindly on 6 mice each at a dose of 100 µmol Fe/kg. Images were acquired (4.7 T Bruker imaging system, Bruker, Ettlingen, Germany) at the level of abdominal aorta with a T2-weighted RARE sequence (TR/TE = 3000/20 ms, RARE factor = 4, NEX = 4, matrix = 256x256, FOV = 2.3 cm, slice thickness 1 mm, 20 axial slices, spatial resolution = 90 µm) and a T2*-weighted FLASH imaging protocol (TR/TE = 175/1.88 ms, flip angle = 90°, NEX = 8, matrix = 128x128, FOV = 2.5 cm, slice thickness 1.25 mm, 15 axial slices, spatial resolution = 172 µm). A 3D-TOF sequence (TR/TE = 10/2 ms, flip angle = 20°, NEX = 2, FOV = 4x2x4 cm, matrix = 256x128x64, slice thickness = 1 mm, 60 axial slices, spatial resolution = 156x156x625 µm) was used with the aim to confirm the anatomical location of the aorta in the image slice. SI values for each time point were measured within ROIs drawn manually by using the ImageJ image analysis software in the arterial wall of the abdominal aorta. The standard deviation (SD) of noise was also measured in a region situated out of the animal's image. SI enhancement (%SNR) was then calculated. VCAM-1 expression in atherosclerotic aorta was confirmed by immunohistochemistry, while contrast agents were stained on aortic samples by Perl's Prussian blue staining protocol. Results The maximum negative contrast produced by USPIO-R832 on RARE images occurred between ~30 min and 94 min post-injection, probably depending on the level of plaque neovascularization, which influences the diffusion of the contrast agent. This could also be a sign of plaque vulnerability. The plaque surface was measured on images and it was correlated to the level of the plaque enhancement and to the histological observations. In the case of FLASH images, the maximum negative contrast occurred between ~40 min and 80 min post-injection. With the exception of one mouse, the negative contrast was almost absent in the case of USPIO-NSP both on RARE and FLASH images. The histochemistry studies confirmed the MRI results and have shown an extensive VCAM-1 expression, as well as the presence of capillary-like structures that could be of angiogenic nature. Conclusions Our peptide-vectorized, VCAM-1-targeted, superparamagnetic imaging probe seems to be a highly promising tool for atherosclerosis imaging, by considering its ability to attain its target in lower doses and as fast as 30 min after administration. This represents an important progress in comparison with previously developed superparamagnetic agents designed for the same purpose. The lower immunogenic potential and the cost-effectiveness when compared with antibody-conjugated contrast agents represent supplementary arguments for a possible implementation in the clinical practice. Bibliography 1. Kelly KA, Allport JR, Tsurkas A, Shinde-Patil VR, Josephson L, Weissleder R, Circ Res, 96, 2005, 327-336. 2. McAteer MA, Schneider JE, Ali ZA, Warrick N, Bursill CA, von zur Muhlen C, Greaves DR, Neubauer S, Channon KM, Choudhury RP, Arterioscler Thromb Vasc Biol, 28, 2008, 77-83. 3. Burtea C, Laurent S, Port M, Lancelot E, Ballet S, Rousseaux O, Toubeau G, Vander Elst L, Corot C, Muller RN, J Med Chem, 52, 2009, 4725-4742. 4. Port M, Corot C, Raynal I, Rousseaux O, US Patent 2004/0253181 A1

Conjugation of Functionalized SPIONs with Transferrin for Targeting and Imaging Brain Glial Tumors in Rat Model

Currently, effective and specific diagnostic imaging of brain glioma is a major challenge. Nanomedicine plays an essential role by delivering the contrast agent in a targeted manner to specific tumor cells, leading to improvement in accurate diagnosis by good visualization and specific demonstration of tumor cells. This study investigated the preparation and characterization of a targeted MR contrast agent, transferrin-conjugated superparamagnetic iron oxide nanoparticles (Tf-SPIONs), for brain glioma detection. MR imaging showed the obvious contrast change of brain glioma before and after administration of Tf-SPIONs in C6 glioma rat model in vivo on T2 weighted imaging. Significant contrast enhancement of brain glioma could still be clearly seen even 48 h post injection, due to the retention of Tf-SPIONs in cytoplasm of tumor cells which was proved by Prussian blue staining. Thus, these results suggest that Tf-SPIONs could be a potential targeting MR contrast agent for the brain glioma

Molecular MRI of Inflammation in Atherosclerosis

Inflammatory activity in atherosclerotic plaque is a risk factor for plaque rupture and atherothrombosis and may direct interventional therapy. Inflammatory activity can be evaluated at the (sub)cellular level using in vivo molecular MRI. This paper reviews recent progress in contrast-enhanced molecular MRI to visualize atherosclerotic plaque inflammation. Various MRI contrast agents, among others ultra-small particles of iron oxide, low-molecular-weight Gd-chelates, micelles, liposomes, and perfluorocarbon emulsions, have been used for in vivo visualization of various inflammation-related targets, such as macrophages, oxidized LDL, endothelial cell expression, plaque neovasculature, MMPs, apoptosis, and activated platelets/thrombus. An enzyme-activatable magnetic resonance contrast agent has been developed to study myeloperoxidase activity in inflamed plaques. Agents creating contrast based on the chemical exchange saturation transfer mechanism were used for thrombus imaging. Transfer of these molecular MRI techniques to the clinic will critically depend on the safety profiles of these newly developed magnetic resonance contrast agents

Phosphatidylserine targeting for diagnosis and treatment of human diseases

Cells are able to execute apoptosis by activating series of specific biochemical reactions. One of the most prominent characteristics of cell death is the externalization of phosphatidylserine (PS), which in healthy cells resides predominantly in the inner leaflet of the plasma membrane. These features have made PS-externalization a well-explored phenomenon to image cell death for diagnostic purposes. In addition, it was demonstrated that under certain conditions viable cells express PS at their surface such as endothelial cells of tumor blood vessels, stressed tumor cells and hypoxic cardiomyocytes. Hence, PS has become a potential target for therapeutic strategies aiming at Targeted Drug Delivery. In this review we highlight the biomarker PS and various PS-binding compounds that have been employed to target PS for diagnostic purposes. We emphasize the 35 kD human protein annexin A5, that has been developed as a Molecular Imaging agent to measure cell death in vitro, and non-invasively in vivo in animal models and in patients with cardiovascular diseases and cancer. Recently focus has shifted from diagnostic towards therapeutic applications employing annexin A5 in strategies to deliver drugs to cells that express PS at their surface

Molecular imaging of inflammation and intraplaque vasa vasorum: A step forward to identification of vulnerable plaques?

Current developments in cardiovascular biology and imaging enable the noninvasive molecular evaluation of atherosclerotic vascular disease. Intraplaque neovascularization sprouting from the adventitial vasa vasorum has been identified as an independent predictor of intraplaque hemorrhage and plaque rupture. These intraplaque vasa vasorum result from angiogenesis, most likely under influence of hypoxic and inflammatory stimuli. Several molecular imaging techniques are currently available. Most experience has been obtained with molecular imaging using positron emission tomography and single photon emission computed tomography. Recently, the development of targeted contrast agents has allowed molecular imaging with magnetic resonance imaging, ultrasound and computed tomography. The present review discusses the use of these molecular imaging techniques to identify inflammation and intraplaque vasa vasorum to identify vulnerable atherosclerotic plaques at risk of rupture and thrombosis. The available literature on molecular imaging techniques and molecular targets associated with inflammation and angiogenesis is discussed, and the clinical applications of molecular cardiovascular imaging and the use of molecular techniques for local drug delivery are addressed