Activated Platelets in Carotid Artery Thrombosis in Mice Can Be Selectively Targeted with a Radiolabeled Single-Chain Antibody

BACKGROUND: Activated platelets can be found on the surface of inflamed, rupture-prone and ruptured plaques as well as in intravascular thrombosis. They are key players in thrombosis and atherosclerosis. In this study we describe the construction of a radiolabeled single-chain antibody targeting the LIBS-epitope of activated platelets to selectively depict platelet activation and wall-adherent non-occlusive thrombosis in a mouse model with nuclear imaging using in vitro and ex vivo autoradiography as well as small animal SPECT-CT for in vivo analysis. METHODOLOGY/PRINCIPAL FINDINGS: LIBS as well as an unspecific control single-chain antibody were labeled with (111)Indium ((111)In) via bifunctional DTPA ( = (111)In-LIBS/(111)In-control). Autoradiography after incubation with (111)In-LIBS on activated platelets in vitro (mean 3866 ± 28 DLU/mm(2), 4010 ± 630 DLU/mm(2) and 4520 ± 293 DLU/mm(2)) produced a significantly higher ligand uptake compared to (111)In-control (2101 ± 76 DLU/mm(2), 1181 ± 96 DLU/mm(2) and 1866 ± 246 DLU/mm(2)) indicating a specific binding to activated platelets; P<0.05. Applying these findings to an ex vivo mouse model of carotid artery thrombosis revealed a significant increase in ligand uptake after injection of (111)In-LIBS in the presence of small thrombi compared to the non-injured side, as confirmed by histology (49630 ± 10650 DLU/mm(2) vs. 17390 ± 7470 DLU/mm(2); P<0.05). These findings could also be reproduced in vivo. SPECT-CT analysis of the injured carotid artery with (111)In-LIBS resulted in a significant increase of the target-to-background ratio compared to (111)In-control (1.99 ± 0.36 vs. 1.1 ± 0.24; P < 0.01). CONCLUSIONS/SIGNIFICANCE: Nuclear imaging with (111)In-LIBS allows the detection of platelet activation in vitro and ex vivo with high sensitivity. Using SPECT-CT, wall-adherent activated platelets in carotid arteries could be depicted in vivo. These results encourage further studies elucidating the role of activated platelets in plaque pathology and atherosclerosis and might be of interest for further developments towards clinical application

Design and baseline characteristics of the finerenone in reducing cardiovascular mortality and morbidity in diabetic kidney disease trial

Background: Among people with diabetes, those with kidney disease have exceptionally high rates of cardiovascular (CV) morbidity and mortality and progression of their underlying kidney disease. Finerenone is a novel, nonsteroidal, selective mineralocorticoid receptor antagonist that has shown to reduce albuminuria in type 2 diabetes (T2D) patients with chronic kidney disease (CKD) while revealing only a low risk of hyperkalemia. However, the effect of finerenone on CV and renal outcomes has not yet been investigated in long-term trials. Patients and Methods: The Finerenone in Reducing CV Mortality and Morbidity in Diabetic Kidney Disease (FIGARO-DKD) trial aims to assess the efficacy and safety of finerenone compared to placebo at reducing clinically important CV and renal outcomes in T2D patients with CKD. FIGARO-DKD is a randomized, double-blind, placebo-controlled, parallel-group, event-driven trial running in 47 countries with an expected duration of approximately 6 years. FIGARO-DKD randomized 7,437 patients with an estimated glomerular filtration rate >= 25 mL/min/1.73 m(2) and albuminuria (urinary albumin-to-creatinine ratio >= 30 to <= 5,000 mg/g). The study has at least 90% power to detect a 20% reduction in the risk of the primary outcome (overall two-sided significance level alpha = 0.05), the composite of time to first occurrence of CV death, nonfatal myocardial infarction, nonfatal stroke, or hospitalization for heart failure. Conclusions: FIGARO-DKD will determine whether an optimally treated cohort of T2D patients with CKD at high risk of CV and renal events will experience cardiorenal benefits with the addition of finerenone to their treatment regimen. Trial Registration: EudraCT number: 2015-000950-39; ClinicalTrials.gov identifier: NCT02545049

Trends in Clinical Trials for Spinal Cord Stimulation

Background: Spinal cord stimulation (SCS) is a neuromodulation technology widely used in the treatment of intractable chronic pain syndromes. SCS is now being applied more broadly as a possible therapy for a range of indications, including neurological, cardiac, and gastrointestinal disorders. Ongoing research in this field is critical in order to gain further insights into the mechanisms of SCS, determine its role in new indications, and refine programming techniques for the optimization of therapeutic outcomes. Objective: To assess the state of SCS-related human research by cataloging and summarizing clinical trials that have been recently completed or are currently underway in this field. Methods: A search was conducted for clinical trials pertaining to SCS using the ClinicalTrials.gov database. Trials were analyzed to generate a detailed overview of ongoing SCS-related research. Specifically, trials were categorized by intervention, trial start date, study completion status, clinical phase, projected subject enrollment, condition, country of origin, device manufacturer, funding source, and study topic. Results: In total, 212 relevant clinical trials were identified. 175 trials (82.5%) involved invasive SCS, while the remaining 37 trials (17.5%) used noninvasive forms of spinal stimulation. Most trials examined the efficacy of SCS for chronic pain syndromes or new indications, while others assessed different stimulation parameters. The studies spanned >27 different disorders, with almost 20% of trials pertaining to conditions other than chronic pain syndromes. The majority of SCS trials were US-based (55.7% of studies), but many countries (e.g., Belgium and UK) are becoming increasingly active. The ratio of investigator-sponsored to industry-sponsored trials was 2:1. Emphasizing the need to optimize therapeutic outcomes of SCS, one-quarter of trials predominantly focused on the assessment of alternative stimulation parameters such as burst or high-frequency stimulation. Conclusions: A large number of clinical trials of SCS are underway. Improvements in the treatment of pain and novel indications for SCS constitute the majority of studies. This overview of SCS-related clinical trials provides a window into future new indications, novel stimulation techniques, and a heightened understanding of the mechanisms of action.This work was supported by the Canadian Institutes of Health Research (I.E.H.), German Research Foundation (Deutsche For- schungsgemeinschaft, DFG NE 2276/1-1) (C.N.), and the Canada Research Chair in Neuroscience (A.M.L.)

The experimental design.

<p>(A) Cartoon depicting the model used for inducing atherothrombosis. A tiny curved needle introduced through a branch of the external carotid was advanced up to the plaque surface under persistent blood flow. After positioning the tip of the needle in front of the plaque, it was applied to the plaque and moved forth and back twice in order to scratch the fibrous cap. (B) The experimental timeline. “I” stands for injection. (C) Transversal histological section of the carotid artery after the scratch injury. Immunohistochemistry depicts platelets and therefore thrombus in red. The scratch with superimposed thrombosis is clearly visible and induced here a small dissection (arrow). A corresponding section of the site of the plaque rupture stained with Masson-Trichrome is depicted in (D).</p

Quantitative analysis of MRI data.

<p>Subgroup analysis of animals with thrombus size >2% is shown in Fig. 3A for animals with LIBS-MPIO and control-MPIO injection. At each time point after the injection of LIBS-MPIO, the MR signal detected at the level of the scratched plaque was significantly lower than the signal detected at the contralateral and non-injured plaque level (A, red line). Conversely, the ratio of signals slightly increased after the injection of control-MPIO (A, blue line). In animals with thrombus size <2%, the signal ratio had not been altered by the injection of LIBS-MPIO in comparison to the injection of control-MPIO (3B).</p

Axial MRI images of the external carotid arteries from two representative animals.

<p>Depicted are four consecutive slices (H1-H4) at three time points: t₍₋₁₎ (before injection), t₂ (16 minutes after injection) and t₃ (24 minutes after injection). Red circles indicate the left external carotid artery which underwent surgery and scratching of the plaque, and green circles mark the contra lateral vessel. The animals orientation is indicated by labeling its posterior (P) and left (L) direction. Signal attenuation can be observed in the animal A which received LIBS-MPIO contrast agent whereas the blood signal remains hyperintense in animal B receiving the control-MPIO.</p

Quantification of MPIOs on histological sections.

<p>MPIOs were about four-fold more abundant in animals with LIBS-MPIO-injection as compared to the animals receiving control-MPIO. A similar difference was observed between injured and non injured vessels in animals receiving LIBS-MPIO. Correlation of thrombus size with the number of bound MPIOs in animals with LIBS-MPIO injection is not significant; however the number of MPIOs is in average within a similar range of 10–20 MPIOs per section as expected from the observed signal attenuation.</p