Review of MR spectroscopy analysis and artificial intelligence applications for the detection of cerebral inflammation and neurotoxicity in Alzheimer's disease

INTRODUCTION

Magnetic resonance spectroscopy (MRS) has an emerging role as a neuroimaging tool for the detection of biomarkers of Alzheimer's disease (AD). To date, MRS has been established as one of the diagnostic tools for various diseases such as breast cancer and fatty liver, as well as brain tumours. However, its utility in neurodegenerative diseases is still in the experimental stages. The potential role of the modality has not been fully explored, as there is diverse information regarding the aberrations in the brain metabolites caused by normal ageing versus neurodegenerative disorders.

MATERIALS AND METHODS

A literature search was carried out to gather eligible studies from the following widely sourced electronic databases such as Scopus, PubMed and Google Scholar using the combination of the following keywords: AD, MRS, brain metabolites, deep learning (DL), machine learning (ML) and artificial intelligence (AI); having the aim of taking the readers through the advancements in the usage of MRS analysis and related AI applications for the detection of AD.

RESULTS

We elaborate on the MRS data acquisition, processing, analysis, and interpretation techniques. Recommendation is made for MRS parameters that can obtain the best quality spectrum for fingerprinting the brain metabolomics composition in AD. Furthermore, we summarise ML and DL techniques that have been utilised to estimate the uncertainty in the machine-predicted metabolite content, as well as streamline the process of displaying results of metabolites derangement that occurs as part of ageing.

CONCLUSION

MRS has a role as a non-invasive tool for the detection of brain metabolite biomarkers that indicate brain metabolic health, which can be integral in the management of AD.

Second Data Release from the European Pulsar Timing Array: Challenging the Ultralight Dark Matter Paradigm

Pulsar Timing Array experiments probe the presence of possible scalar or pseudoscalar ultralight dark matter particles through decade-long timing of an ensemble of galactic millisecond radio pulsars. With the second data release of the European Pulsar Timing Array, we focus on the most robust scenario, in which dark matter interacts only gravitationally with ordinary baryonic matter. Our results show that ultralight particles with masses 10^{-24.0}  eV≲m≲10^{-23.3}  eV cannot constitute 100% of the measured local dark matter density, but can have at most local density ρ≲0.3  GeV/cm^{3}.

Anticoagulant treatment patterns and thromboembolic events by tumor type among patients with VTE and cancer

Background

Patients with venous thromboembolism (VTE) and cancer are at higher risk of adverse outcomes (mortality, recurrent VTE etc.) versus patients with cancer alone; as such, clinical guidelines recommend anticoagulant treatment for patients with VTE and cancer. There is limited real world data about how anticoagulant treatment and thromboembolic outcomes differ by tumor type in patients with VTE and cancer. Understanding such differences may help identify appropriate anticoagulant treatment for specific tumor types.

Purpose

To describe anticoagulant treatment patterns and thromboembolic outcomes by tumor type among patients with VTE and cancer.

Methods

Patients with VTE and cancer age ≥65 were identified from the Surveillance, Epidemiology and End Results (SEER) Medicare database from 1/1/2014–12/31/2019. Patients were required to be enrolled for ≥6-months prior to their first VTE diagnosis (index) and without evidence of other conditions requiring anticoagulant (i.e., atrial fibrillation) prior to index. Cancer status and tumor type were identified from SEER or Medicare database in the 6-months prior through 30-days post VTE. This analysis focused on the following specific tumor types: high risk (brain, pancreas, and stomach) and common tumor types (breast, and prostate). Patients treated with an anticoagulant within 30-days after index were included in the final population. Major bleeding (MB) and recurrent VTE events were measured during follow-up (index date through earliest of disenrollment, death or 12/31/2019).

Results

A total of 3,546 anticoagulated patients with VTE and cancer of interest met all study criteria (breast [n=1,197], prostate [n=849], pancreatic [n=995], brain [n=248] and stomach [n=257] cancer). Patient mean age ranged from 73 (brain) to 76 (stomach) at index. Anticoagulant treatment patterns varied by tumor type (Figure 1). LMWH was more likely to be used in the 3 high risk tumor types whereas apixaban and rivaroxaban were more likely to be used in the 2 common tumor types. The incidence rate of recurrent VTE and major bleeding events also varied among different tumor types: ranging from 1.4 (breast) to 6.4 (pancreatic) per 100 person-years for recurrent VTE and from 4.3 (prostate) to 15.1 (pancreatic) per 100 person-years for major bleeding (Figure 2).

Conclusion

There are notable variations in anticoagulant treatment patters and the risks of major bleeding and recurrent VTE events by tumor type among patients with VTE and cancer. Further research is needed to understand which anticoagulant treatment option is more appropriate for VTE patients with specific tumor type.

Funding Acknowledgement

Type of funding sources: Private company. Main funding source(s): Pfizer Inc. and Bristol Myers Squibb Company

CD26-inhibition correlates with the absence of chronic lung allograft dysfunction and decreases fibroblast activity in vitro

Objective

Chronic lung allograft dysfunction (CLAD) limits the survival after lung transplantation (Tx). CLAD is characterized by progressive fibrosis of small airways and lung parenchyma. No effective therapy is available that reverses or prevents CLAD. CD26 is a molecule with enzymatic activity also playing a key role in the progression of fibrotic diseases. Here, we analyzed the inhibitory effect of CD26 on fibroblast activity in vitro and the role of CD26-inhibition on allograft rejection in lung transplant patients.

Methods

Profibrogenic mRNA and protein levels were analyzed in vitro on the CD26-expressing fibroblast cell line Wi-38 using RT-qPCR and Western blot. CD26 was inhibited by Vildagliptin. Migration and proliferation activity of activated fibroblasts were analyzed by Incucyte® and Celltiter-Glo®. Characteristics of patients undergoing lung Tx between 2004 and 2021 were reviewed. Lung biopsies were analyzed by immunohistochemistry (IHC) for CD26.

Results

In vitro, the expression of profibrogenic genes (αSMA, FAPα, IGFBP7, Collagen 3 and Fibronectin) was significantly reduced in activated lung fibroblasts by Vildagliptin treatment. Also, migration and proliferation activity were attenuated by Vildagliptin. In 221 patients analyzed, CLAD was absent in 34 patients treated with the CD26-inhibitor Sitagliptin vs. an incidence of 18% in patients without Sitagliptin intake (p=0.02). Five-year survival in patients on Sitagliptin was significantly improved vs. patients without CD26-inhibitor intake (80% vs. 58%, p=0.006). Likewise, the incidence of acute cellular rejection (ACR) was significantly reduced in patients on Sitagliptin (7% vs. 35%, p=0.01). IHC of patient lung biopsies showed expression of CD26 in perifibrotic areas of CLAD lesions. Additional clinical data from University Hospital Zurich and from University Hospital Padua confirmed the finding that Sitagliptin intake correlated with the absence of acute and chronic allograft rejection.

Conclusion

CD26-inhibition attenuates key pro-fibrotic mediators and fibroblast activity in vitro. Impressively, patients on CD26-inhibitor did not show any CLAD. Moreover, ACR was significantly reduced. Gliptins which are in routine clinical use for the treatment of type II diabetes therefore seem to have great potential to be repurposed for a novel clinical application against lung allograft rejection.

Volumetric Measurement of Relative CBV Using T1-Perfusion-Weighted MRI with High Temporal Resolution Compared with Traditional T2*-Perfusion-Weighted MRI in Postoperative Patients with High-Grade Gliomas

BACKGROUND AND PURPOSE

T1-PWI with high temporal resolution may provide a reliable relative CBV value as a valid alternative to T2*-PWI under increased susceptibility. The purpose of this study was to assess the technical and clinical performance of T1-relative CBV in patients with postoperative high-grade gliomas.

MATERIALS AND METHODS

Forty-five MRIs of 34 patients with proved high-grade gliomas were included. In all MRIs, T1- and T2*-PWIs were both acquired and processed semiautomatically to generate relative CBV maps using a released commercial software. Lesion masks were overlaid on the relative CBV maps, followed by a histogram of the whole VOI. The intraclass correlation coefficient and Bland-Altman plots were used for quantitative and qualitative comparisons. Signal loss from both methods was compared using the Wilcoxon signed-rank test of zero voxel percentage. The MRIs were divided into a progression group (n = 20) and a nonprogression group (n = 14) for receiver operating characteristic curve analysis.

RESULTS

Fair intertechnique consistency was observed between the 90th percentiles of the T1- and T2*-relative CBV values (intraclass correlation coefficient = 0.558, P < .001). T2*-PWI revealed a significantly higher percentage of near-zero voxels than T1-PWI (17.7% versus 3.1%, P < .001). There was no statistically significant difference between the area under the curve of T1- and T2*-relative CBV (0.811 versus 0.793, P = .835). T1-relative CBV showed 100% sensitivity and 57.1% specificity for the detection of progressive lesions.

CONCLUSIONS

T1-relative CBV demonstrated exquisite diagnostic performance for detecting progressive lesions in postoperative patients with high-grade gliomas, suggesting the potential role of T1-PWI as a valid alternative to the traditional T2*-PWI.

Attenuation of intrinsic aging of the skin via elimination of senescent dermal fibroblasts with senolytic drugs

BACKGROUND

Skin aging is caused by numerous factors that result in structural and functional changes in cutaneous components. Research has shown that senescent cells are known to accumulate in skin aging, however, the role of senescent cells in skin aging has not been defined.

OBJECTIVES

To elucidate the role of senescent cell in skin aging, we evaluated the effect of known senolytic drugs on senescent dermal fibroblasts.

METHODS

Primary human dermal fibroblasts (HDFs) were induced to senescence by long-term passaging, UV irradiation, and H2O2 treatment. Cell viability was measured after treatment of ABT-263 and ABT-737 on HDFs. Young and aged hairless mice were intradermally injected with drugs or vehicle on the dorsal skin for 10 days. Skin specimens were obtained and reverse-transcription quantitative PCR, western blotting, and histological analysis were performed.

RESULTS

We found that ABT-263 and ABT-737 induced selective clearance of senescent dermal fibroblasts, regardless of the method of senescence induction. Aged mouse skin treated with ABT-263 or ABT-737 showed increased collagen density, epidermal thickness, and proliferation of keratinocytes, as well as decreased senescence-associated secretory phenotypes, such as MMP-1 and IL-6.

CONCLUSIONS

Taken together, our results indicate that selective clearance of senescent skin cells can attenuate and improve skin aging phenotypes and that senolytic drugs may be of potential use as new therapeutic agents for treating aging of the skin.

Intraindividual Comparison between the Contrast-Enhanced Golden-Angle Radial Sparse Parallel Sequence and the Conventional Fat-Suppressed Contrast-Enhanced T1-Weighted Spin-Echo Sequence for Head and Neck MRI

BACKGROUND AND PURPOSE

The golden-angle radial sparse parallel-volumetric interpolated breath-hold (GRASP-VIBE) sequence is a recently introduced imaging technique with high resolution. This study compared the image quality between conventional fat-suppressed T1-weighted TSE and GRASP-VIBE after gadolinium enhancement in the head and neck region.

MATERIALS AND METHODS

Data from 65 patients with clinical indications for head and neck MR imaging between September 2020 and January 2021 were retrospectively reviewed. Two radiologists assessed the overall image quality, overall artifacts, and image conspicuities in the oropharynx, hypopharynx, and cervical lymph nodes according to 5-point scores (best score: 5). Interobserver agreement was assessed using weighted κ statistics. The SNR and contrast-to-noise ratio were calculated and compared between the 2 sequences using a paired Wilcoxon signed rank test.

RESULTS

The analysis included 52 patients (mean age, 60 [SD, 14 ] years; male, 71.2% [37/52]) who were mostly diagnosed with head and neck malignancies (94.3% [50/52]). κ statistics ranged from slight agreement in cervical lymph node conspicuity (κ = 0.18) to substantial agreement in oropharyngeal mucosal conspicuity (κ = 0.80) (κ range, 0.18-0.80). Moreover, GRASP-VIBE demonstrated significantly higher mean scores in overall image quality (4.68 [SD, 0.41] versus 3.66 [SD, 0.73]), artifacts (4.47 [SD, 0.48] versus 3.58 [SD, 0.71]), oropharyngeal mucosal conspicuity (4.85 [SD, 0.41] versus 4.11 [SD, 0.79]), hypopharyngeal mucosal conspicuity (4.84 [SD, 0.34] versus 3.58 [SD, 0.81]), and cervical lymph node conspicuity (4.79 [SD, 0.32] versus 4.08 [SD, 0.64]) than fat-suppressed T1-weighted TSE (all, P < .001). Furthermore, GRASP-VIBE demonstrated a higher SNR (22.8 [SD, 11.5] versus 11.3 [SD, 5.6], P < .001) and contrast-to-noise ratio (4.7 [SD, 5.4] versus 2.3 [SD, 2.7], P = .059) than fat-suppressed T1-weighted TSE.

CONCLUSIONS

GRASP-VIBE provided better image quality with fewer artifacts than conventional fat-suppressed T1-weighted TSE for the head and neck regions.

Airway Epithelial Cells Drive Airway Smooth Muscle Cell Phenotype Switching to the Proliferative and Pro-inflammatory Phenotype

The increased mass of airway smooth muscle (ASM) in the airways of asthmatic patients may contribute to the pathology of this disease by increasing the capacity for airway narrowing. Evidence for the airway epithelium as a participant in ASM remodeling is accruing. To investigate mechanisms by which airway epithelial cells induce ASM cell (ASMC) proliferation, we have employed a co-culture model to explore markers of ASMC proliferative phenotype. Co-culture with epithelial cells led to incorporation of bromodeoxyuridine into ASMCs, indicating augmented proliferation and an associated increase in mRNA of the pro-proliferative co-transcription factor Elk1. Although the mitogen heparin-binding epidermal growth factor (HB-EGF) was augmented in the co-culture supernatant, the ASMC epidermal growth factor receptor (EGFR), an effector of HB-EGF induced proliferation, did not mediate epithelial-induced proliferation. The co-culture increased the expression of ASMC mRNA for the pro-inflammatory cytokines IL-6 and IL-8 as well as the pro-proliferative microRNA miR-210. The transcriptional repressor Max-binding protein (Mnt), a putative target of miR-210, was transcriptionally repressed in co-cultured ASMCs. Together, these data indicate that the airway epithelium-induced proliferative phenotype of ASMCs is not driven by EGFR signaling, but rather may be dependent on miR210 targeting of tumor suppressor Mnt.

Determination of in vitro dry matter, protein, and fiber digestibility and fermentability of novel corn coproducts for swine and ruminants

New processes are being used in some dry-grind ethanol plants in the United States and Brazil to improve ethanol yield and efficiency of production while also providing nutritionally enhanced corn coproducts compared with conventional corn distillers dried grains with solubles (DDGS). The objectives of this study were to determine the chemical composition and in vitro digestibility of 5 conventional corn DDGS sources and 10 emerging novel corn coproducts for swine and ruminants, and compare coproducts produced using similar processes in the United States and Brazil. Chemical composition, on a dry matter (DM) basis, among the 15 coproducts ranged from 18.5% to 54.7% for crude protein (CP), 12.3% to 51.4% for neutral detergent fiber (NDF), 1.6% to 8.6% for acid detergent fiber, 4.7% to 12.3% for ether extract, and 1.6% to 8.6% for ash. For swine, in vitro hydrolysis of DM and CP were greater (P < 0.01) for the three U.S. corn DDGS sources compared with the two Brazilian corn DDGS sources, but in vitro fermentability of DM was comparable (P > 0.05) among all sources except one U.S. DDGS source that had less fermentable DM. High-protein and yeast dried distillers grains (Ultramax, UM; StillPro, SP) coproducts also had comparable (P > 0.05) DM fermentability for swine, but UM coproducts had greater (P < 0.01) DM and CP hydrolysis compared with SP. High-protein distillers dried grains (HP-DDG) from Brazil had greater (P < 0.01) DM and CP hydrolysis, but less (P < 0.01) DM fermentability for swine than HP-DDG produced in the United States, using the same process. For ruminants, total DM digestibility was greater (P < 0.01) in conventional DDGS sources from the United States compared with the two DDGS sources from Brazil. Total protein digestibility for ruminants was comparable and above 81% for all coproducts except for a DDGS source from Brazil, a HP-DDG source from the United States, and a UM sample. Interestingly, the corn fiber + solubles coproduct had not only relatively high digestibility of NDF (67.9%), DM (91.6%), and total CP (81.9%) for ruminants, but it also had relatively high total tract digestibility of DM (86.2%) and CP (69.9%) for swine. These results suggest that nutrient digestibility of conventional DDGS sources produced in the United States appear to be greater than corn Brazilian DDGS sources, but new process technologies being implemented in ethanol and coproduct production in both countries can enhance the nutritional value of corn coproducts for both swine and ruminants.

Irisin promotes odontogenic differentiation and angiogenic potential in human dental pulp cells

AIM

To determine whether irisin, a newly discovered myokine that links exercise-induced and metabolic homeostasis, is able to promote odontogenic differentiation and angiogenesis in human dental pulp cells (HDPCs).

METHODOLOGY

Cell viability in the presence of irisin was measured. Real-time PCR and Western blot analysis were performed to evaluate the expression levels of irisin, odontogenic and angiogenic markers. The involvement of mitogen-activated protein kinase (MAPK) and the protein kinase B (Akt) signalling pathway was evaluated by Western blot. To evaluate mineralization nodule formation, alkaline phosphatase (ALP) staining and alizarin red S staining were performed. Scratch wound assays were performed to evaluate the effects of irisin on cell migration. The data were analysed using one-way analysis of variance (anova) followed by Tukey post hoc test and Student's t-test. Statistical significance was considered at P < 0.05.

RESULTS

Irisin significantly promoted odontogenic differentiation as evidenced by formation of mineralized nodules, induction of ALP activity and upregulation of odontogenic and angiogenic markers (P < 0.05). Scratch wound assays revealed that irisin significantly increased migration of HDPCs (P < 0.05). Phosphorylation of both MAPK and Akt was increased by irisin. MAPK and Akt inhibitors inhibited mineralization, cell migration and the increased expression of odontogenic and angiogenic markers.

CONCLUSIONS

Irisin promoted odontogenic differentiation and mineralization and has the potential for angiogenesis through activation of the MAPK and Akt signalling pathways in HDPCs.

Prediction of Human Papillomavirus Status and Overall Survival in Patients with Untreated Oropharyngeal Squamous Cell Carcinoma: Development and Validation of CT-Based Radiomics

BACKGROUND AND PURPOSE

Human papillomavirus is a prognostic marker for oropharyngeal squamous cell carcinoma. We aimed to determine the value of CT-based radiomics for predicting the human papillomavirus status and overall survival in patients with oropharyngeal squamous cell carcinoma.

MATERIALS AND METHODS

Eighty-six patients with oropharyngeal squamous cell carcinoma were retrospectively collected and grouped into training (n = 61) and test (n = 25) sets. For human papillomavirus status and overall survival prediction, radiomics features were selected via a random forest-based algorithm and Cox regression analysis, respectively. Relevant features were used to build multivariate Cox regression models and calculate the radiomics score. Human papillomavirus status and overall survival prediction were assessed via the area under the curve and concordance index, respectively. The models were validated in the test and The Cancer Imaging Archive cohorts (n = 78).

RESULTS

For prediction of human papillomavirus status, radiomics features yielded areas under the curve of 0.865, 0.747, and 0.834 in the training, test, and validation sets, respectively. In the univariate Cox regression, the human papillomavirus status (positive: hazard ratio, 0.257; 95% CI, 0.09-0.7; P = .008), T-stage (≥III: hazard ratio, 3.66; 95% CI, 1.34-9.99; P = .011), and radiomics score (high-risk: hazard ratio, 3.72; 95% CI, 1.21-11.46; P = .022) were associated with overall survival. The addition of the radiomics score to the clinical Cox model increased the concordance index from 0.702 to 0.733 (P = .01). Validation yielded concordance indices of 0.866 and 0.720.

CONCLUSIONS

CT-based radiomics may be useful in predicting human papillomavirus status and overall survival in patients with oropharyngeal squamous cell carcinoma.

0047 The Change in Melatonin Rhythm Depending on Dementia Severity in Alzheimer’s Disease (AD) Patients

Introduction

In Alzheimer’s disease (AD), both sleep and circadian dysfunctions are commonly reported and these are associated with neurodegenerative change. Actually, it has been reported that changes in circadian rhythms in AD were apparently discrete from those seen in normal aging. Previous studies reported the delayed phase in the activity or core body temperature rhythms in severe AD patients compared to normal controls. However, it is unknown whether similar changes in melatonin rhythms occur in AD patients who were not severely demented. We aimed to compare melatonin rhythms depending on dementia severity in mild and moderate AD patients.

Methods

We recruited AD patients of mild or moderate degree who had the Pittsburgh Sleep Quality Index (PSQI) score of 5 or greater and/or complained insomnia symptoms more than 3 times a week for a month. The patients were classified according to their Clinical Dementia Rating (CDR) score into 3 groups (CDR=0.5, 1, 2). The dim light melatonin onset (DLMO) was determined from seven hourly saliva samples obtained in the laboratory prior to sleep onset measured by actigraphy. The phase angle between the DLMO and sleep onset (PA-SO), and that between the DLMO and midsleep time (PA-MST) were calculated. Each group included 13, 13 and 6 AD patients with the CDR score of 0.5, 1 and 2, respectively. The DLMO and PA were compared among the 3 groups, and correlation analyses of the DLMO and PA with the MMSE in the Korean version of CERAD Packet (MMSE-KC) scores were done in total patients.

Results

There was no significant difference in the DLMO and PA between the 3 groups. The MMSE-KC score was positively correlated with the DLMO and negatively correlated with the PA-MST.

Conclusion

There were no changes in melatonin rhythms according to dementia severity in mild and moderate AD patients with sleep complaints. However, our study showed that earlier melatonin phase was associated with more impaired cognitive function.

Support

Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Science, ICT & Future Planning (2017R1A2B4003493)