Metabolite Study and Structural Authentication for the First-in-Human Use Sphingosine-1-phosphate Receptor 1 Radiotracer.

The sphingosine-1-phosphate receptor 1 (S1PR1) radiotracer [11C]CS1P1 has shown promise in proof-of-concept PET imaging of neuroinflammation in multiple sclerosis (MS). Our HPLC radiometabolite analysis of human plasma samples collected during PET scans with [11C]CS1P1 detected a radiometabolite peak that is more lipophilic than [11C]CS1P1. Radiolabeled metabolites that cross the blood-brain barrier complicate quantitative modeling of neuroimaging tracers; thus, characterizing such radiometabolites is important. Here, we report our detailed investigation of the metabolite profile of [11C]CS1P1 in rats, nonhuman primates, and humans. CS1P1 is a fluorine-containing ligand that we labeled with C-11 or F-18 for preclinical studies; the brain uptake was similar for both radiotracers. The same lipophilic radiometabolite found in human studies also was observed in plasma samples of rats and NHPs for CS1P1 labeled with either C-11 or F-18. We characterized the metabolite in detail using rats after injection of the nonradioactive CS1P1. To authenticate the molecular structure of this radiometabolite, we injected rats with 8 mg/kg of CS1P1 to collect plasma for solvent extraction and HPLC injection, followed by LC/MS analysis of the same metabolite. The LC/MS data indicated in vivo mono-oxidation of CS1P1 produces the metabolite. Subsequently, we synthesized three different mono-oxidized derivatives of CS1P1 for further investigation. Comparing the retention times of the mono-oxidized derivatives with the metabolite observed in rats injected with CS1P1 identified the metabolite as N-oxide 1, also named TZ82121. The MS fragmentation pattern of N-oxide 1 also matched that of the major metabolite in rat plasma. To confirm that metabolite TZ82121 does not enter the brain, we radiosynthesized [18F]TZ82121 by the oxidation of [18F]FS1P1. Radio-HPLC analysis confirmed that [18F]TZ82121 matched the radiometabolite observed in rat plasma post injection of [18F]FS1P1. Furthermore, the acute biodistribution study in SD rats and PET brain imaging in a nonhuman primate showed that [18F]TZ82121 does not enter the rat or nonhuman primate brain. Consequently, we concluded that the major lipophilic radiometabolite N-oxide [11C]TZ82121, detected in human plasma post injection of [11C]CS1P1, does not enter the brain to confound quantitative PET data analysis. [11C]CS1P1 is a promising S1PR1 radiotracer for detecting S1PR1 expression in the CNS.

Synthesis of bioengineered heparin chemically and biologically similar to porcine-derived products and convertible to low MW heparin.

Heparins have been invaluable therapeutic anticoagulant polysaccharides for over a century, whether used as unfractionated heparin or as low molecular weight heparin (LMWH) derivatives. However, heparin production by extraction from animal tissues presents multiple challenges, including the risk of adulteration, contamination, prion and viral impurities, limited supply, insecure supply chain, and significant batch-to-batch variability. The use of animal-derived heparin also raises ethical and religious concerns, as well as carries the risk of transmitting zoonotic diseases. Chemoenzymatic synthesis of animal-free heparin products would offer several advantages, including reliable and scalable production processes, improved purity and consistency, and the ability to produce heparin polysaccharides with molecular weight, structural, and functional properties equivalent to those of the United States Pharmacopeia (USP) heparin, currently only sourced from porcine intestinal mucosa. We report a scalable process for the production of bioengineered heparin that is biologically and compositionally similar to USP heparin. This process relies on enzymes from the heparin biosynthetic pathway, immobilized on an inert support and requires a tailored N-sulfoheparosan with N-sulfo levels similar to those of porcine heparins. We also report the conversion of our bioengineered heparin into a LMWH that is biologically and compositionally similar to USP enoxaparin. Ultimately, we demonstrate major advances to a process to provide a potential clinical and sustainable alternative to porcine-derived heparin products.

Alternating magnetic fields drive stimulation of gene expression via generation of reactive oxygen species.

Magnetogenetics represents a method for remote control of cellular function. Previous work suggests that generation of reactive oxygen species (ROS) initiates downstream signaling. Herein, a chemical biology approach was used to elucidate further the mechanism of radio frequency-alternating magnetic field (RF-AMF) stimulation of a TRPV1-ferritin magnetogenetics platform that leads to Ca2+ flux. RF-AMF stimulation of HEK293T cells expressing TRPV1-ferritin resulted in ∼30% and ∼140% increase in intra- and extracellular ROS levels, respectively. Mutations to specific cysteine residues in TRPV1 responsible for ROS sensitivity eliminated RF-AMF driven Ca2+-dependent transcription of secreted embryonic alkaline phosphatase (SEAP). Using a non-tethered (to TRPV1) ferritin also eliminated RF-AMF driven SEAP production, and using specific inhibitors, ROS-activated TRPV1 signaling involves protein kinase C, NADPH oxidase, and the endoplasmic reticulum. These results suggest ferritin-dependent ROS activation of TRPV1 plays a key role in the initiation of magnetogenetics, and provides relevance for potential applications in medicine and biotechnology.

Improving Early Recognition of Treatment-Responsive Causes of Rapidly Progressive Dementia: The STAM3 P Score.

OBJECTIVE: To improve the timely recognition of patients with treatment-responsive causes of rapidly progressive dementia (RPD). METHODS: A total of 226 adult patients with suspected RPD were enrolled in a prospective observational study and followed for up to 2 years. Diseases associated with RPD were characterized as potentially treatment-responsive or non-responsive, referencing clinical literature. Disease progression was measured using Clinical Dementia Rating® Sum-of-Box scores. Clinical and paraclinical features associated with treatment responsiveness were assessed using multivariable logistic regression. Findings informed the development of a clinical criterion optimized to recognize patients with potentially treatment-responsive causes of RPD early in the diagnostic evaluation. RESULTS: A total of 155 patients met defined RPD criteria, of whom 86 patients (55.5%) had potentially treatment-responsive causes. The median (range) age-at-symptom onset in patients with RPD was 68.9 years (range 22.0-90.7 years), with a similar number of men and women. Seizures, tumor (disease-associated), magnetic resonance imaging suggestive of autoimmune encephalitis, mania, movement abnormalities, and pleocytosis (≥10 cells/mm3 ) in cerebrospinal fluid at presentation were independently associated with treatment-responsive causes of RPD after controlling for age and sex. Those features at presentation, as well as age-at-symptom onset <50 years (ie, STAM3 P), captured 82 of 86 (95.3%) cases of treatment-responsive RPD. The presence of ≥3 STAM3 P features had a positive predictive value of 100%. INTERPRETATION: Selected features at presentation reliably identified patients with potentially treatment-responsive causes of RPD. Adaptation of the STAM3 P screening score in clinical practice may minimize diagnostic delays and missed opportunities for treatment in patients with suspected RPD. ANN NEUROL 2024;95:237-248.

Diagnostic Utility of Cerebrospinal Fluid Biomarkers in Patients with Rapidly Progressive Dementia.

OBJECTIVE: This study was undertaken to apply established and emerging cerebrospinal fluid (CSF) biomarkers to improve diagnostic accuracy in patients with rapidly progressive dementia (RPD). Overlap in clinical presentation and results of diagnostic tests confounds etiologic diagnosis in patients with RPD. Objective measures are needed to improve diagnostic accuracy and to recognize patients with potentially treatment-responsive causes of RPD. METHODS: Biomarkers of Alzheimer disease neuropathology (amyloid-ß 42/40 ratio, phosphorylated tau [p-tau181, p-tau231]), neuroaxonal/neuronal injury (neurofilament light chain [NfL], visinin-like protein-1 [VILIP-1], total tau), neuroinflammation (chitinase-3-like protein [YKL-40], soluble triggering receptor expressed on myeloid cells 2 [sTREM2], glial fibrillary acidic protein [GFAP], monocyte chemoattractant protein-1 [MCP-1]), and synaptic dysfunction (synaptosomal-associated protein 25kDa, neurogranin) were measured in CSF obtained at presentation from 78 prospectively accrued patients with RPD due to neurodegenerative, vascular, and autoimmune/inflammatory diseases; 35 age- and sex-matched patients with typically progressive neurodegenerative disease; and 72 cognitively normal controls. Biomarker levels were compared across etiologic diagnoses, by potential treatment responsiveness, and between patients with typical and rapidly progressive presentations of neurodegenerative disease. RESULTS: Alzheimer disease biomarkers were associated with neurodegenerative causes of RPD. High NfL, sTREM2, and YKL-40 and low VILIP-1 identified patients with autoimmune/inflammatory diseases. MCP-1 levels were highest in patients with vascular causes of RPD. A multivariate model including GFAP, MCP-1, p-tau181, and sTREM2 identified the 44 patients with treatment-responsive causes of RPD with 89% accuracy. Minimal differences were observed between typical and rapidly progressive presentations of neurodegenerative disease. INTERPRETATION: Selected CSF biomarkers at presentation were associated with etiologic diagnoses and treatment responsiveness in patients with heterogeneous causes of RPD. The ability of cross-sectional biomarkers to inform upon mechanisms that drive rapidly progressive neurodegenerative disease is less clear. ANN NEUROL 2024;95:299-313.

Magnetogenetic cell activation using endogenous ferritin.

The ability to precisely control the activity of defined cell populations enables studies of their physiological roles and may provide therapeutic applications. While prior studies have shown that magnetic activation of ferritin-tagged ion channels allows cell-specific modulation of cellular activity, the large size of the constructs made the use of adeno-associated virus, AAV, the vector of choice for gene therapy, impractical. In addition, simple means for generating magnetic fields of sufficient strength have been lacking. Toward these ends, we first generated a novel anti-ferritin nanobody that when fused to transient receptor potential cation channel subfamily V member 1, TRPV1, enables direct binding of the channel to endogenous ferritin in mouse and human cells. This smaller construct can be delivered in a single AAV and we validated that it robustly enables magnetically induced cell activation in vitro . In parallel, we developed a simple benchtop electromagnet capable of gating the nanobody-tagged channel in vivo . Finally, we showed that delivering these new constructs by AAV to pancreatic beta cells in combination with the benchtop magnetic field delivery stimulates glucose-stimulated insulin release to improve glucose tolerance in mice in vivo . Together, the novel anti-ferritin nanobody, nanobody-TRPV1 construct and new hardware advance the utility of magnetogenetics in animals and potentially humans.

T1 and FLAIR signal intensities are related to tau pathology in dominantly inherited Alzheimer disease.

Carriers of mutations responsible for dominantly inherited Alzheimer disease provide a unique opportunity to study potential imaging biomarkers. Biomarkers based on routinely acquired clinical MR images, could supplement the extant invasive or logistically challenging) biomarker studies. We used 1104 longitudinal MR, 324 amyloid beta, and 87 tau positron emission tomography imaging sessions from 525 participants enrolled in the Dominantly Inherited Alzheimer Network Observational Study to extract novel imaging metrics representing the mean (µ) and standard deviation (σ) of standardized image intensities of T1-weighted and Fluid attenuated inversion recovery (FLAIR) MR scans. There was an exponential decrease in FLAIR-µ in mutation carriers and an increase in FLAIR and T1 signal heterogeneity (T1-σ and FLAIR-σ) as participants approached the symptom onset in both supramarginal, the right postcentral and right superior temporal gyri as well as both caudate nuclei, putamina, thalami, and amygdalae. After controlling for the effect of regional atrophy, FLAIR-µ decreased and T1-σ and FLAIR-σ increased with increasing amyloid beta and tau deposition in numerous cortical regions. In symptomatic mutation carriers and independent of the effect of regional atrophy, tau pathology demonstrated a stronger relationship with image intensity metrics, compared with amyloid pathology. We propose novel MR imaging intensity-based metrics using standard clinical T1 and FLAIR images which strongly associates with the progression of pathology in dominantly inherited Alzheimer disease. We suggest that tau pathology may be a key driver of the observed changes in this cohort of patients.

Quantitative Analysis of S1PR1 Expression in the Postmortem Multiple Sclerosis Central Nervous System.

Multiple sclerosis (MS) is an immune-mediated disease that is characterized by demyelination and inflammation in the central nervous system (CNS). Previous studies demonstrated that sphingosine-1-phosphate receptor (S1PR) modulators effectively inhibit S1PR1 in immune cell trafficking and reduce entry of pathogenic cells into the CNS. Studies have also implicated a nonimmune, inflammatory role of S1PR1 within the CNS in MS. In this study, we explored the expression of S1PR1 in the development and progression of demyelinating pathology of MS by quantitative assessment of S1PR1 expression using our S1PR1-specific radioligand, [3H]CS1P1, in the postmortem human CNS tissues including cortex, cerebellum, and spinal cord of MS cases and age- and sex-matched healthy cases. Immunohistochemistry with whole slide scanning for S1PR1 and various myelin proteins was also performed. Autoradiographic analysis using [3H]CS1P1 showed that the expression of S1PR1 was statistically significantly elevated in lesions compared to nonlesion regions in the MS cases, as well as normal healthy controls. The uptake of [3H]CS1P1 in the gray matter and nonlesion white matter did not significantly differ between healthy and MS CNS tissues. Saturation autoradiography analysis showed an increased binding affinity (Kd) of [3H]CS1P1 to S1PR1 in both gray matter and white matter of MS brains compared to healthy brains. Our blocking study using NIBR-0213, a S1PR1 antagonist, indicated [3H]CS1P1 is highly specific to S1PR1. Our findings demonstrated the activation of S1PR1 and an increased uptake of [3H]CS1P1 in the lesions of MS CNS. In summary, our quantitative autoradiography analysis using [3H]CS1P1 on human postmortem tissues shows the feasibility of novel imaging strategies for MS by targeting S1PR1.

Measuring Pathology in Patients with Multiple Sclerosis Using Positron Emission Tomography.

PURPOSE OF REVIEW: Multiple sclerosis is characterized by a diverse and complex pathology. Clinical relapses, the hallmark of the disease, are accompanied by focal white matter lesions with intense inflammatory and demyelinating activity. Prevention of these relapses has been the major focus of pharmaceutical development, and it is now possible to dramatically reduce this inflammatory activity. Unfortunately, disability accumulation persists for many people living with multiple sclerosis owing to ongoing damage within existing lesions, pathology outside of discrete lesions, and other yet unknown factors. Understanding this complex pathological cascade will be critical to stopping progressive multiple sclerosis. Positron emission tomography uses biochemically specific radioligands to quantitatively measure pathological processes with molecular specificity. This review examines recent advances in the understanding of multiple sclerosis facilitated by positron emission tomography and identifies future avenues to expand understanding and treatment options. RECENT FINDINGS: An increasing number of radiotracers allow for the quantitative measurement of inflammatory abnormalities, de- and re-myelination, and metabolic disruption associated with multiple sclerosis. The studies have identified contributions of ongoing, smoldering inflammation to accumulating tissue injury and clinical worsening. Myelin studies have quantified the dynamics of myelin loss and recovery. Lastly, metabolic changes have been found to contribute to symptom worsening. The molecular specificity facilitated by positron emission tomography in people living with multiple sclerosis will critically inform efforts to modulate the pathology leading to progressive disability accumulation. Existing studies show the power of this approach applied to multiple sclerosis. This armamentarium of radioligands allows for new understanding of how the brain and spinal cord of people is impacted by multiple sclerosis.

Quantitative MRI identifies lesional and non-lesional abnormalities in MOGAD.

BACKGROUND: Myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD) is a distinct central nervous system (CNS) disorder that shares features with multiple sclerosis (MS) and may be misdiagnosed as MS. MOGAD and MS share a frequently relapsing clinical course and lesions with inflammatory demyelinating pathology. One key feature of MS pathology is tissue damage in normal-appearing white matter (NAWM) outside of discrete lesions, whereas the extent to which similar non-lesional damage occurs in MOGAD is not known and could be assessed using qGRE. The goal of this study was to examine the brains of people with MOGAD using quantitative gradient-recalled echo (qGRE) magnetic resonance imaging and to compare tissue damage with MS patients matched for disability. METHODS: MOGAD and MS patients were recruited to match in terms of age and disability. Similarly aged healthy control (HC) data were drawn from existing studies. qGRE brain imaging of HC (N = 15), MOGAD (N = 17), and MS (N = 15) patients was used to examine the severity and extent of tissue damage within and outside of discrete lesions. The qGRE metric R2t* is sensitive to changes in tissue microstructure and was measured in white matter lesions (WMLs), NAWM, cortical (CGM) and deep gray matter (DGM). Statistical inference was performed with linear models. RESULTS: R2t* was reduced in CGM (p = 0.00047), DGM (p = 0.0055) and NAWM (p = 0.0019) in MOGAD and MS compared to similar regions in age-matched HCs. However, the degree of R2t* reduction in all these regions was less in the MOGAD patients compared with MS. WMLs in MOGAD demonstrated reduced R2t* compared to NAWM but this reduction was modest compared to changes associated with WMLs in MS (p = 0.026). CONCLUSION: These results demonstrate abnormalities in lesional and non-lesional CNS tissues in MOGAD that are not detectable on standard MRI. The abnormalities seen in NAWM, CGM, and DGM were less severe in MOGAD compared to MS. MOGAD-related WMLs showed reduced R2t*, but were less abnormal than WMLs in MS. These data reveal damage to non-lesional tissues in two different demyelinating diseases, suggesting that damage outside of WMLs may be a common feature of demyelinating diseases. The lesser degree of R2t* abnormality in MOGAD tissues compared to MS suggests less underlying tissue damage and may underlie the greater propensity for recovery in MOGAD.

"Brain age" predicts disability accumulation in multiple sclerosis.

OBJECTIVE: Neurodegenerative conditions often manifest radiologically with the appearance of premature aging. Multiple sclerosis (MS) biomarkers related to lesion burden are well developed, but measures of neurodegeneration are less well-developed. The appearance of premature aging quantified by machine learning applied to structural MRI assesses neurodegenerative pathology. We assess the explanatory and predictive power of "brain age" analysis on disability in MS using a large, real-world dataset. METHODS: Brain age analysis is predicated on the over-estimation of predicted brain age in patients with more advanced pathology. We compared the performance of three brain age algorithms in a large, longitudinal dataset (>13,000 imaging sessions from >6,000 individual MS patients). Effects of MS, MS disease course, disability, lesion burden, and DMT efficacy were assessed using linear mixed effects models. RESULTS: MS was associated with advanced predicted brain age cross-sectionally and accelerated brain aging longitudinally in all techniques. While MS disease course (relapsing vs. progressive) did contribute to advanced brain age, disability was the primary correlate of advanced brain age. We found that advanced brain age at study enrollment predicted more disability accumulation longitudinally. Lastly, a more youthful appearing brain (predicted brain age less than actual age) was associated with decreased disability. INTERPRETATION: Brain age is a technically tractable and clinically relevant biomarker of disease pathology that correlates with and predicts increasing disability in MS. Advanced brain age predicts future disability accumulation.

Real-time quaking-induced conversion assays for prions: Applying a sensitive but imperfect test in clinical practice.

BACKGROUND AND PURPOSE: Real-time quaking-induced conversion (RT-QuIC) assays offer a sensitive and specific means for detection of prions, although false negative results are recognized in clinical practice. We profile the clinical, laboratory, and pathologic features associated with false negative RT-QuIC assays and extend these to frame the diagnostic approach to patients with suspected prion disease. METHODS: A total of 113 patients with probable or definite prion disease were assessed at Mayo Clinic (Rochester, MN; Jacksonville, FL; Scottsdale, AZ) or Washington University School of Medicine (Saint Louis, MO) from 2013 to 2021. RT-QuIC testing for prions was performed in cerebrospinal fluid (CSF) at the National Prion Disease Pathology Surveillance Center (Cleveland, OH). RESULTS: Initial RT-QuIC testing was negative in 13 of 113 patients (sensitivity = 88.5%). RT-QuIC negative patients were younger (median = 52.0 years vs. 66.1 years, p < 0.001). Other demographic and presenting features, and CSF cell count, protein, and glucose levels were similar in RT-QuIC negative and positive patients. Frequency of 14-3-3 positivity (4/13 vs. 77/94, p < 0.001) and median CSF total tau levels were lower in RT-QuIC negative patients (2517 vs. 4001 pg/mL, p = 0.020), and time from symptom onset to first presentation (153 vs. 47 days, p = 0.001) and symptomatic duration (710 vs. 148 days, p = 0.001) were longer. CONCLUSIONS: RT-QuIC is a sensitive yet imperfect measure necessitating incorporation of other test results when evaluating patients with suspected prion disease. Patients with negative RT-QuIC had lower markers of neuronal damage (CSF total tau and protein 14-3-3) and longer symptomatic duration of disease, suggesting that false negative RT-QuIC testing associates with a more indolent course.

Covariance-based vs. correlation-based functional connectivity dissociates healthy aging from Alzheimer disease.

Prior studies of aging and Alzheimer disease have evaluated resting state functional connectivity (FC) using either seed-based correlation (SBC) or independent component analysis (ICA), with a focus on particular functional systems. SBC and ICA both are insensitive to differences in signal amplitude. At the same time, accumulating evidence indicates that the amplitude of spontaneous BOLD signal fluctuations is physiologically meaningful. We systematically compared covariance-based FC, which is sensitive to amplitude, vs. correlation-based FC, which is not, in affected individuals and controls drawn from two cohorts of participants including autosomal dominant Alzheimer disease (ADAD), late onset Alzheimer disease (LOAD), and age-matched controls. Functional connectivity was computed over 222 regions of interest and group differences were evaluated in terms of components projected onto a space of lower dimension. Our principal observations are: (1) Aging is associated with global loss of resting state fMRI signal amplitude that is approximately uniform across resting state networks. (2) Thus, covariance FC measures decrease with age whereas correlation FC is relatively preserved in healthy aging. (3) In contrast, symptomatic ADAD and LOAD both lead to loss of spontaneous activity amplitude as well as severely degraded correlation structure. These results demonstrate a double dissociation between age vs. Alzheimer disease and the amplitude vs. correlation structure of resting state BOLD signals. Modeling results suggest that the AD-associated loss of correlation structure is attributable to a relative increase in the fraction of locally restricted as opposed to widely shared variance.

Phase 1 Evaluation of 11C-CS1P1 to Assess Safety and Dosimetry in Human Participants.

This study evaluated the safety, dosimetry, and characteristics of 3-((2-fluoro-4-(5-(2'-methyl-2-(trifluoromethyl)-[1,1'-biphenyl]-4-yl)-1,2,4-oxadiazol-3-yl)benzyl)(methyl-11C)amino)propanoic acid (11C-CS1P1), a radiotracer targeting sphingosine-1-phosphate receptor (S1PR) 1 (S1PR1). S1PR1 is of clinical interest because of its role in multiple sclerosis (and other conditions), with an expanding class of S1PR modulators approved for relapsing multiple sclerosis. 11C-CS1P1 binds S1PR1 with high specificity and has shown promise in animal models of inflammatory diseases. Methods: 11C-CS1P1 was injected into 5 male and 6 female healthy participants. Ten participants were imaged with PET using a multipass whole-body continuous-bed-motion acquisition, and one had dedicated head and neck PET and MRI. Participants were continuously monitored for safety events. Organ time-activity curve data were collected, integrated, and normalized to the injected activity. Organ radiation doses and effective dose were computed using the adult male and female models in OLINDA, version 2.2. SUV images were evaluated for qualitative biodistribution. Results: No adverse events were observed after the dose, including no bradycardia. The liver was the critical organ from dosimetry analysis (mean ± SD: female, 23.12 ± 5.19 µSv/MBq; male, 21.06 ± 1.63 µSv/MBq). The whole-body effective dose (as defined by International Commission on Radiological Protection publication 103) was 4.18 ± 0.30 µSv/MBq in women and 3.54 ± 0.14 µSv/MBq in men. Using a maximum delivered dose of 740 MBq (20 mCi), the effective dose for women would be 3.1 mSv (0.31 rem), with a liver dose of 17.1 mSv (1.7 rem); the effective dose for men would be 2.6 mSv (0.26 rem), with a liver dose of 15.6 mSv (1.56 rem). Brain uptake was seen predominantly in gray matter and correlated with regional S1PR1 RNA expression (r = 0.84). Conclusion: These results support the safety of 11C-CS1P1 for evaluation of inflammation in human clinical populations. Dosimetry permits repeated measures in the same participants. Brain uptake correlates well with known target topography.

Tissue damage detected by quantitative gradient echo MRI correlates with clinical progression in non-relapsing progressive MS.

BACKGROUND: Imaging biomarkers of progressive multiple sclerosis (MS) are needed. Quantitative gradient recalled echo (qGRE) magnetic resonance imaging (MRI) evaluates microstructural tissue damage in MS. OBJECTIVE: To evaluate qGRE-derived R2t* as an imaging biomarker of MS progression compared with atrophy and lesion burden. METHODS: Twenty-three non-relapsing progressive MS (PMS), 22 relapsing-remitting MS (RRMS), and 18 healthy control participants underwent standard MS physical and cognitive neurological assessments and imaging with qGRE, FLAIR, and MPRAGE at 3T. PMS subjects were tested clinically and imaged every 9 months over 45 months. Imaging measures included lesion burden, atrophy, and R2t* in cortical gray matter (GM), deep GM, and normal-appearing white matter (NAWM). Longitudinal analysis of clinical performance and imaging biomarkers in PMS subjects was conducted via linear models with subject as repeated, within-subject factor. Relationship between imaging biomarkers and clinical scores was assessed by Spearman rank correlation. RESULTS: R2t* reductions correlated with neurological impairment cross-sectionally and longitudinally. PMS patients with clinically defined disease progression (N = 13) showed faster decrease of R2t* in NAWM and deep GM compared with the clinically stable PMS group (N = 10). Importantly, tissue damage measured by R2t* outperformed lesion burden and atrophy as a biomarker of progression during the study period. CONCLUSION: qGRE-derived R2t* is a potential imaging biomarker of MS progression.

Central vein sign and other radiographic features distinguishing myelin oligodendrocyte glycoprotein antibody disease from multiple sclerosis and aquaporin-4 antibody-positive neuromyelitis optica.

BACKGROUND: Myelin oligodendrocyte glycoprotein antibody disease (MOGAD) can radiographically mimic multiple sclerosis (MS) and aquaporin-4 (AQP4) antibody-positive neuromyelitis optica spectrum disorder (NMOSD). Central vein sign (CVS) prevalence has not yet been well-established in MOGAD. OBJECTIVE: Characterize the magnetic resonance imaging (MRI) appearance and CVS prevalence of MOGAD patients in comparison to matched cohorts of MS and AQP4+ NMOSD. METHODS: Clinical MRIs from 26 MOGAD patients were compared to matched cohorts of MS and AQP4+ NMOSD. Brain MRIs were assessed for involvement within predefined regions of interest. CVS was assessed by overlaying fluid-attenuated inversion recovery (FLAIR) and susceptibility-weighted sequences. Topographic analyses were performed on spinal cord and orbital MRIs when available. RESULTS: MOGAD patients had fewer brain lesions and average CVS+ rate of 12.1%, compared to 44.4% in MS patients (p = 0.0008). MOGAD spinal cord and optic nerve involvement was lengthier than MS (5.8 vs 1.0 vertebral segments, p = 0.020; 3.0 vs 0.5 cm, p < 0.0001). MOGAD patients tended to have bilateral/anterior optic nerve pathology with perineural contrast enhancement, contrasting with posterior optic nerve involvement in NMOSD. CONCLUSION: CVS+ rate and longer segments of involvement in the spinal cord and optic nerve can differentiate MOGAD from MS, but do not discriminate as well between MOGAD and AQP4+ NMOSD.

Increased white matter glycolysis in humans with cerebral small vessel disease.

White matter lesions in cerebral small vessel disease are related to ischemic injury and increase the risk of stroke and cognitive decline. Pathological changes due to cerebral small vessel disease are increasingly recognized outside of discrete lesions, but the metabolic alterations in nonlesional tissue has not been described. Aerobic glycolysis is critical to white matter myelin homeostasis and repair. In this study, we examined cerebral metabolism of glucose and oxygen as well as blood flow in individuals with and without cerebral small vessel disease using multitracer positron emission tomography. We show that glycolysis is relatively elevated in nonlesional white matter in individuals with small vessel disease relative to healthy, age-matched controls. On the other hand, in young healthy individuals, glycolysis is relatively low in areas of white matter susceptible to lesion formation. These results suggest that increased white matter glycolysis is a marker of pathology associated with small vessel disease.

Facile fabrication of antibacterial and antiviral perhydrolase-polydopamine composite coatings.

In situ generation of antibacterial and antiviral agents by harnessing the catalytic activity of enzymes on surfaces provides an effective eco-friendly approach for disinfection. The perhydrolase (AcT) from Mycobacterium smegmatis catalyzes the perhydrolysis of acetate esters to generate the potent disinfectant, peracetic acid (PAA). In the presence of AcT and its two substrates, propylene glycol diacetate and H2O2, sufficient and continuous PAA is generated over an extended time to kill a wide range of bacteria with the enzyme dissolved in aqueous buffer. For extended self-disinfection, however, active and stable AcT bound onto or incorporated into a surface coating is necessary. In the current study, an active, stable and reusable AcT-based coating was developed by incorporating AcT into a polydopamine (PDA) matrix in a single step, thereby forming a biocatalytic composite onto a variety of surfaces. The resulting AcT-PDA composite coatings on glass, metal and epoxy surfaces yielded up to 7-log reduction of Gram-positive and Gram-negative bacteria when in contact with the biocatalytic coating. This composite coating also possessed potent antiviral activity, and dramatically reduced the infectivity of a SARS-CoV-2 pseudovirus within minutes. The single-step approach enables rapid and facile fabrication of enzyme-based disinfectant composite coatings with high activity and stability, which enables reuse following surface washing. As a result, this enzyme-polymer composite technique may serve as a general strategy for preparing antibacterial and antiviral surfaces for applications in health care and common infrastructure safety, such as in schools, the workplace, transportation, etc.

Appraisal of Health States Worse Than Death in Patients With Acute Stroke.

OBJECTIVE: To identify health states that patients with acute stroke deem worse than death and to explore potential predictors for these ratings. METHODS: This was a cross-sectional study involving patients admitted to an urban comprehensive stroke center with acute stroke. Participants were asked to rate 10 possible health states/functional outcomes as better or worse than death using a 5-point Likert scale. Principal component analysis (PCA) was used to reduce clusters of correlated ratings to summary components (factors). These components were then analyzed using linear regression to identify possible predictive variables. RESULTS: Eighty patients participated. The states deemed equal to or worse than death by the majority of participants were relying on a breathing machine (66%) or feeding tube (66%), persistent confusion (62%), inability to communicate with others (58%), and bowel/bladder incontinence (50%). PCA revealed 2 factors of correlated variables: factor 1 composed primarily of relying on a feeding tube or breathing machine, incontinence, chronic pain, and persistent confusion, and factor 2 composed primarily of using a wheelchair, being bedbound, living in a nursing home, and requiring help for activities of daily living. The only significant predictor found was race for factor 1, with black participants finding these states more preferable to death than white participants. DISCUSSION: A substantial number of patients found multiple common outcomes of stroke to be the same as or worse than death. This highlights the importance of realistic discussions about expected functional outcomes with patients and/or their surrogate decision makers when considering goals of care after stroke.

Quantitative signal properties from standardized MRIs correlate with multiple sclerosis disability.

OBJECTIVE: To enable use of clinical magnetic resonance images (MRIs) to quantify abnormalities in normal appearing (NA) white matter (WM) and gray matter (GM) in multiple sclerosis (MS) and to determine associations with MS-related disability. Identification of these abnormalities heretofore has required specialized scans not routinely available in clinical practice. METHODS: We developed an analytic technique which normalizes image intensities based on an intensity atlas for quantification of WM and GM abnormalities in standardized MRIs obtained with clinical sequences. Gaussian mixture modeling is applied to summarize image intensity distributions from T1-weighted and 3D-FLAIR (T2-weighted) images from 5010 participants enrolled in a multinational database of MS patients which collected imaging, neuroperformance and disability measures. RESULTS: Intensity distribution metrics distinguished MS patients from control participants based on normalized non-lesional signal differences. This analysis revealed non-lesional differences between relapsing MS versus progressive MS subtypes. Further, the correlation between our non-lesional measures and disability was approximately three times greater than that between total lesion volume and disability, measured using the patient derived disease steps. Multivariate modeling revealed that measures of extra-lesional tissue integrity and atrophy contribute uniquely, and approximately equally, to the prediction of MS-related disability. INTERPRETATION: These results support the notion that non-lesional abnormalities correlate more strongly with MS-related disability than lesion burden and provide new insight into the basis of abnormalities in NA WM. Non-lesional abnormalities distinguish relapsing from progressive MS but do not distinguish between progressive subtypes suggesting a common progressive pathophysiology. Image intensity parameters and existing biomarkers each independently correlate with MS-related disability.