External evaluation of a deep learning-based approach for automated brain volumetry in patients with huntington's disease

A crucial step in the clinical adaptation of an AI-based tool is an external, independent validation. The aim of this study was to investigate brain atrophy in patients with confirmed, progressed Huntington's disease using a certified software for automated volumetry and to compare the results with the manual measurement methods used in clinical practice as well as volume calculations of the caudate nuclei based on manual segmentations. Twenty-two patients were included retrospectively, consisting of eleven patients with Huntington's disease and caudate nucleus atrophy and an age- and sex-matched control group. To quantify caudate head atrophy, the frontal horn width to intercaudate distance ratio and the intercaudate distance to inner table width ratio were obtained. The software mdbrain was used for automated volumetry. Manually measured ratios and automatically measured volumes of the groups were compared using two-sample t-tests. Pearson correlation analyses were performed. The relative difference between automatically and manually determined volumes of the caudate nuclei was calculated. Both ratios were significantly different between the groups. The automatically and manually determined volumes of the caudate nuclei showed a high level of agreement with a mean relative discrepancy of - 2.3 ± 5.5%. The Huntington's disease group showed significantly lower volumes in a variety of supratentorial brain structures. The highest degree of atrophy was shown for the caudate nucleus, putamen, and pallidum (all p < .0001). The caudate nucleus volume and the ratios were found to be strongly correlated in both groups. In conclusion, in patients with progressed Huntington's disease, it was shown that the automatically determined caudate nucleus volume correlates strongly with measured ratios commonly used in clinical practice. Both methods allowed clear differentiation between groups in this collective. The software additionally allows radiologists to more objectively assess the involvement of a variety of brain structures that are less accessible to standard semiquantitative methods.

Pharmacological characterization of P2Y receptor subtypes - an update

P2Y receptors are G-protein-coupled receptors (GPCRs) for extracellular nucleotides. There are eight mammalian P2Y receptor subtypes (P2Y1, P2Y2, P2Y4, P2Y6, P2Y11, P2Y12, P2Y13, and P2Y14). The widely expressed P2Y receptors play important roles in physiology and pathophysiology. This review summarizes the use of pharmacological tools to characterize the P2Y receptor subtypes involved in these responses. MRS2500 is a potent and selective antagonist acting at the P2Y1 receptor. AR-C118925 is useful for the selective antagonism of the P2Y2 receptor. PSB16133 blocks the P2Y4 receptor, MRS2578 is an antagonist at the P2Y6 receptor and NF157 as well as NF340 block the P2Y11 receptor. ADP-induced platelet aggregation is mediated by P2Y1 and P2Y12 receptors. A number of compounds or their active metabolites reduce ADP-induced platelet aggregation by blocking the P2Y12 receptor. These include the active metabolites of the thienopyridine compounds clopidogrel and prasugrel, the nucleoside analogue ticagrelor and the nucleotide analogue cangrelor. PSB0739 is also a potent antagonist at the P2Y12 receptor useful for both in vitro and in vivo studies. MRS2211 and MRS2603 inhibit P2Y13 mediated responses. PPTN is a very potent antagonist at the P2Y14 receptor.

Comparison of Arctic Front Advance Pro and POLARx cryoballoons for ablation therapy of atrial fibrillation: an intraprocedural analysis

INTRODUCTION

Cryoballoon (CB) ablation has become a popular method for pulmonary vein isolation (PVI) in atrial fibrillation (AF) treatment. This study aimed to compare the intraprocedural ablation characteristics of two cryoballoons, Arctic Front Advance Pro™ (AFA-Pro, Medtronic) and POLARx™ (Boston Scientific).

METHODS AND RESULTS

In this retrospective single-center study, 230 symptomatic paroxysmal or persistent AF patients underwent CB ablation with either AFA-Pro or POLARx. Propensity-score matching resulted in two cohorts of 114 patients each. Baseline and procedural characteristics were comparable between both CBs. POLARx achieved lower minimal temperatures (e.g., left superior pulmonary vein, LSPV: AFA-Pro - 49.0 °C vs. POLARx - 59.5 °C) and lower temperatures at time-to-isolation (TTI). Additionally, POLARx reached lower temperatures faster, as evidenced by lower temperatures after 40 and 60 s, and a larger mean temperature change between 20 and 40 s. POLARx also had a greater area under the curve below 0 °C and a longer thawing phase. Both CBs achieved comparable high rates of final PV-isolation. TTI, minimal esophagus temperature, and first-pass isolation rates were similar between groups. Periprocedural complications, including phrenic nerve injuries, were comparable. Troponin levels in the left atrium were elevated with both systems. Values and change in troponin were numerically higher in the POLARx group (delta troponin: AFA-Pro 36.3 (26.4, 125.4) ng/L vs. POLARx 104.9 (49.5, 122.2) ng/L), p = 0.077).

CONCLUSION

AFA-Pro and POLARx are both highly effective and safe CB systems for PVI. POLARx exhibited significant faster and lower freezing characteristics, and numerically higher troponin levels might indicate greater myocardial injury. However, these differences did not translate into improved performance, procedural efficiency, or safety.

The Meteoritics Trial: efficacy of methotrexate after remission-induction with tocilizumab and glucocorticoids in giant cell arteritis-study protocol for a randomized, double-blind, placebo-controlled, parallel-group phase II study

BACKGROUND

Glucocorticoids (GC) are the standard treatment for giant cell arteritis (GCA), even though they are associated with adverse side effects and high relapse rates. Tocilizumab (TCZ), an interleukin-6 receptor antagonist, has shown promise in sustaining remission and reducing the cumulative GC dosage, but it increases the risk of infections and is expensive. After discontinuation of TCZ, only about half of patients remain in remission. Additionally, only few studies have been conducted looking at remission maintenance, highlighting the need for alternative strategies to maintain remission in GCA. Methotrexate (MTX) has been shown to significantly decrease the risk of relapse in new-onset GCA and is already a proven safe drug in many rheumatologic diseases.

METHODS

This study aims to evaluate the efficacy and safety of MTX in maintaining remission in patients with GCA who have previously been treated with GC and at least 6 months with TCZ. We hypothesize that MTX can maintain remission in GCA patients, who have achieved stable remission after treatment with GC and TCZ, and prevent the occurrence of relapses. The study design is a monocentric, randomized, double-blind, placebo-controlled, parallel-group phase II trial randomizing 40 GCA patients 1:1 into a MTX or placebo arm. Patients will receive 17.5 mg MTX/matching placebo weekly by subcutaneous injection for 12 months, with the possibility of dose reduction if clinically needed. A 6-month follow-up will take place. The primary endpoint is the time to first relapse in the MTX group versus placebo during the 12-month treatment period. Secondary outcomes include patient- and investigator-reported outcomes and laboratory findings, as well as the prevalence of aortitis, number of vasculitic vessels, and change in intima-media thickness during the study.

DISCUSSION

This is the first clinical trial evaluating remission maintenance of GCA with MTX after a previous treatment cycle with TCZ. Following the discontinuation of TCZ in GCA, MTX could be a safe and inexpensive drug.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT05623592. Registered on 21 November 2022. EU Clinical Trials Register, 2022-501058-12-00. German Clinical Trials Register DRKS00030571.

Long-term effects of chronic stress models in adult mice

Neuropsychiatric disorders, such as major depression, anxiety disorders, and post-traumatic stress disorder, tend to be long-term conditions in whose development and maintenance stress are central pathogenic factors. Translational mouse models are widely used in neuropsychiatric research, exploiting social and non-social stressors to investigate the mechanisms underlying their detrimental effects. However, most studies focus on the short-term consequences of chronic stress, whereas only a few are interested in the long-term course. This is counterintuitive given the human conditions that preclinical models are designed to mimic. In this review, we have summarized the limited work to date on long-term effects of chronic stress in mice models. First, the different models are presented and a definition of short- vs. long-term sequelae is proposed. On this basis, behavioral, endocrine, and vegetative effects are addressed before examining data on cellular and molecular alterations in the brain. Finally, future directions for research on the long-term effects of stress are discussed.

Proteomic investigation of neural stem cell to oligodendrocyte precursor cell differentiation reveals phosphorylation-dependent Dclk1 processing

Oligodendrocytes are generated via a two-step mechanism from pluripotent neural stem cells (NSCs): after differentiation of NSCs to oligodendrocyte precursor/NG2 cells (OPCs), they further develop into mature oligodendrocytes. The first step of this differentiation process is only incompletely understood. In this study, we utilized the neurosphere assay to investigate NSC to OPC differentiation in a time course-dependent manner by mass spectrometry-based (phospho-) proteomics. We identify doublecortin-like kinase 1 (Dclk1) as one of the most prominently regulated proteins in both datasets, and show that it undergoes a gradual transition between its short/long isoform during NSC to OPC differentiation. This is regulated by phosphorylation of its SP-rich region, resulting in inhibition of proteolytic Dclk1 long cleavage, and therefore Dclk1 short generation. Through interactome analyses of different Dclk1 isoforms by proximity biotinylation, we characterize their individual putative interaction partners and substrates. All data are available via ProteomeXchange with identifier PXD040652.

A novel and simple cardiac magnetic resonance score (PE2RT) predicts outcome in takotsubo syndrome

OBJECTIVES

To find simple imaging-based features on cardiac magnetic resonance (CMR) that are associated with major adverse cardiovascular events (MACE) in takotsubo syndrome (TTS).

METHODS

Patients with TTS referred for CMR between 2007 and 2021 were retrospectively evaluated. Besides standard CMR analysis, commonly known complications of TTS based on expert knowledge were assessed and summarised via a newly developed PE2RT score (one point each for pleural effusion, pericardial effusion, right ventricular involvement, and ventricular thrombus). Clinical follow-up data was reviewed up to three years after discharge. The relationship between PE2RT features and the occurrence of MACE (cardiovascular death or new hospitalisation due to acute myocardial injury, arrhythmia, or chronic heart failure) was examined using Cox regression analysis and Kaplan-Meier estimator.

RESULTS

Seventy-nine patients (mean age, 68 ± 14 years; 72 women) with TTS were included. CMR was performed in a median of 4 days (IQR, 2-6) after symptom onset. Over a median follow-up of 13.3 months (IQR, 0.4-36.0), MACE occurred in 14/79 (18%) patients: re-hospitalisation due to acute symptoms (9/79, 11%) or chronic heart failure symptoms (4/79, 5%), and cardiac death (1/79, 1%). Patients with MACE had a higher PE2RT score (median [IQR], 2 [2-3] vs 1 [0-1]; p < 0.001). PE2RT score was associated with MACE on Cox regression analysis (hazard ratio per PE2RT feature, 2.44; 95%CI: 1.62-3.68; p < 0.001). Two or more PE2RT complications were strongly associated with the occurrence of MACE (log-rank p < 0.001).

CONCLUSIONS

The introduced PE2RT complication score might enable an easy-to-assess outcome evaluation of TTS patients by CMR.

KEY POINTS

• Complications like pericardial effusion, pleural effusion, right ventricular involvement, and ventricular thrombus (summarised as PE2RT features) are relatively common in takotsubo syndrome. • The proposed PE2RT score (one point per complication) was associated with the occurrence of major adverse cardiac events on follow-up. • Complications easily detected by cardiac magnetic resonance imaging can help clinicians derive long-term prognostic information on patients with takotsubo syndrome.

Spatial patterns of white matter hyperintensities: a systematic review

Background

White matter hyperintensities are an important marker of cerebral small vessel disease. This disease burden is commonly described as hyperintense areas in the cerebral white matter, as seen on T2-weighted fluid attenuated inversion recovery magnetic resonance imaging data. Studies have demonstrated associations with various cognitive impairments, neurological diseases, and neuropathologies, as well as clinical and risk factors, such as age, sex, and hypertension. Due to their heterogeneous appearance in location and size, studies have started to investigate spatial distributions and patterns, beyond summarizing this cerebrovascular disease burden in a single metric-its volume. Here, we review the evidence of association of white matter hyperintensity spatial patterns with its risk factors and clinical diagnoses.

Design/methods

We performed a systematic review in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) Statement. We used the standards for reporting vascular changes on neuroimaging criteria to construct a search string for literature search on PubMed. Studies written in English from the earliest records available until January 31st, 2023, were eligible for inclusion if they reported on spatial patterns of white matter hyperintensities of presumed vascular origin.

Results

A total of 380 studies were identified by the initial literature search, of which 41 studies satisfied the inclusion criteria. These studies included cohorts based on mild cognitive impairment (15/41), Alzheimer's disease (14/41), Dementia (5/41), Parkinson's disease (3/41), and subjective cognitive decline (2/41). Additionally, 6 of 41 studies investigated cognitively normal, older cohorts, two of which were population-based, or other clinical findings such as acute ischemic stroke or reduced cardiac output. Cohorts ranged from 32 to 882 patients/participants [median cohort size 191.5 and 51.6% female (range: 17.9-81.3%)]. The studies included in this review have identified spatial heterogeneity of WMHs with various impairments, diseases, and pathologies as well as with sex and (cerebro)vascular risk factors.

Conclusion

The results show that studying white matter hyperintensities on a more granular level might give a deeper understanding of the underlying neuropathology and their effects. This motivates further studies examining the spatial patterns of white matter hyperintensities.

Cutaneous Lupus Erythematosus: An Update on Pathogenesis and Future Therapeutic Directions

Lupus erythematosus comprises a spectrum of autoimmune diseases that may affect various organs (systemic lupus erythematosus [SLE]) or the skin only (cutaneous lupus erythematosus [CLE]). Typical combinations of clinical, histological and serological findings define clinical subtypes of CLE, yet there is high interindividual variation. Skin lesions arise in the course of triggers such as ultraviolet (UV) light exposure, smoking or drugs; keratinocytes, cytotoxic T cells and plasmacytoid dendritic cells (pDCs) establish a self-perpetuating interplay between the innate and adaptive immune system that is pivotal for the pathogenesis of CLE. Therefore, treatment relies on avoidance of triggers and UV protection, topical therapies (glucocorticosteroids, calcineurin inhibitors) and rather unspecific immunosuppressive or immunomodulatory drugs. Yet, the advent of licensed targeted therapies for SLE might also open new perspectives in the management of CLE. The heterogeneity of CLE might be attributable to individual variables and we speculate that the prevailing inflammatory signature defined by either T cells, B cells, pDCs, a strong lesional type I interferon (IFN) response, or combinations of the above might be suitable to predict therapeutic response to targeted treatment. Therefore, pretherapeutic histological assessment of the inflammatory infiltrate could stratify patients with refractory CLE for T-cell-directed therapies (e.g. dapirolizumab pegol), B-cell-directed therapies (e.g. belimumab), pDC-directed therapies (e.g. litifilimab) or IFN-directed therapies (e.g. anifrolumab). Moreover, Janus kinase (JAK) and spleen tyrosine kinase (SYK) inhibitors might broaden the therapeutic armamentarium in the near future. A close interdisciplinary exchange with rheumatologists and nephrologists is mandatory for optimal treatment of lupus patients to define the best therapeutic strategy.

Non-contrast free-breathing 3D cardiovascular magnetic resonance angiography using REACT (relaxation-enhanced angiography without contrast) compared to contrast-enhanced steady-state magnetic resonance angiography in complex pediatric congenital heart disease at 3T

BACKGROUND

To evaluate the great vessels in young children with complex congenital heart disease (CHD) using non-contrast cardiovascular magnetic resonance angiography (CMRA) based on three-dimensional relaxation-enhanced angiography without contrast (REACT) in comparison to contrast-enhanced steady-state CMRA.

METHODS

In this retrospective study from April to July 2021, respiratory- and electrocardiogram-gated native REACT CMRA was compared to contrast-enhanced single-phase steady-state CMRA in children with CHD who underwent CMRA at 3T under deep sedation. Vascular assessment included image quality (1 = non-diagnostic, 5 = excellent), vessel diameter, and diagnostic findings. For statistical analysis, paired t-test, Pearson correlation, Bland-Altman analysis, Wilcoxon test, and intraclass correlation coefficients (ICC) were applied.

RESULTS

Thirty-six young children with complex CHD (median 4 years, interquartile range, 2-5; 20 males) were included. Native REACT CMRA was obtained successfully in all patients (mean scan time: 4:22 ± 1:44 min). For all vessels assessed, diameters correlated strongly between both methods (Pearson r = 0.99; bias = 0.04 ± 0.61 mm) with high interobserver reproducibility (ICC: 0.99 for both CMRAs). Native REACT CMRA demonstrated comparable overall image quality to contrast-enhanced CMRA (3.9 ± 1.0 vs. 3.8 ± 0.9, P = 0.018). With REACT CMRA, better image quality was obtained at the ascending aorta (4.8 ± 0.5 vs. 4.3 ± 0.8, P < 0.001), coronary roots (e.g., left: 4.1 ± 1.0 vs. 3.3 ± 1.1, P = 0.001), and inferior vena cava (4.6 ± 0.5 vs. 3.2 ± 0.8, P < 0.001). In all patients, additional vascular findings were assessed equally with native REACT CMRA and the contrast-enhanced reference standard (n = 6).

CONCLUSION

In young children with complex CHD, REACT CMRA can provide gadolinium-free high image quality, accurate vascular measurements, and equivalent diagnostic quality compared to standard contrast-enhanced CMRA.