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Natascha Schurz,1,* Lydia Sariaslani,1,* Patrick Altmann,1 Fritz Leutmezer,1 Christoph Mitsch,2 Berthold Pemp,2 Paulus Rommer,1 Tobias Zrzavy,1 Thomas Berger,1 Gabriel Bsteh1 1Department of Neurology, Medical University of Vienna, Vienna, Austria; 2Department of Ophthalmology, Medical University of Vienna, Vienna, Austria*These authors contributed equally to this workCorrespondence: Gabriel BstehMedical University of Vienna, Waehringer Guertel 18-20, Vienna, 1090, AustriaTel +43 1 40400 31450Email gabriel.bsteh@meduniwien.ac.atPurpose: Retinal layer thickness parameters measured by optical coherence tomography (OCT) are emerging biomarkers of neuroaxonal degeneration and inflammation in multiple sclerosis (MS). We aimed to evaluate the value of retinal layer thickness for prediction of disability worsening and relapse in a real-world MS cohort.Patients and Methods: For this longitudinal observational study, we included MS patients with spectral-domain OCT scans available and ≥ 1 year of clinical follow-up. The value of peripapillary retinal nerve fiber layer (pRNFL), macular ganglion-cell-and-inner-plexiform-layer (GCIPL) and inner nuclear layer (INL) thickness for prediction of disability worsening and relapse during the observation period was tested by multivariate models.Results: We analyzed 60 MS patients during a mean observation period of 2.9 years (SD 1.8). Lower baseline thickness of GCIPL (cut-off < 77μm; HR 4.1, p=0.001) and pRNFL (cut-off ≤ 88μm; HR 3.1, p=0.019) were associated with an increased risk of disability worsening. Longitudinally, mean thinning rates were − 0.8μm/year (SD 1.6) for GCIPL, − 0.6μm/year (SD 3.5) for pRNFL. GCIPL thinning ≥ 1.0μm/year and pRNFL > 1.5μm/year is associated with higher likelihood of disability worsening (HR 5.7, p=0.009 and HR 6.8, p=0.003, respectively). INL thickened in patients with relapse by a mean 0.9μm while thinning by 0.3μm in patients without relapse (p=0.04). In multivariate analyses, INL thickening was associated with an increased probability of relapse (OR 17.8, p=0.023).Conclusion: Cross-sectional and longitudinal measurement of GCIPL and pRNFL thinning is reliable as a biomarker of disability worsening in a real-world setting. Change of INL thickness is a promising marker of relapse, i.e. inflammatory activity.Keywords: multiple sclerosis, biomarker, optical coherence tomography, retinal thinning, progression, relapse

Abstract Acute transverse myelitis (ATM) is a disease characterized by inflammation of the spinal cord and may have various causes. In the context of this work, the distinction between isolated ATM and initial manifestation of autoimmune-mediated diseases of the central nervous system such as multiple sclerosis (MS) is crucial. Hence, the aim of this work was to identify predictive factors associated with the conversion to definite MS in a collective of individuals after their initial episode of isolated ATM (no initial identified cause). In this retrospective data analysis from the Vienna MS Database, all patients from Jan. 1, 1999, to Dec. 31, 2019, with a diagnosis of isolated ATM (according to the criteria of the Transverse Myelitis Consortium Working Group) who underwent lumbar puncture were extracted. Electronic medical records were reviewed on the availability of clinical data including therapy and follow-up, laboratory results including cerebrospinal fluid (CSF) analysis, evoked potentials (EP) as well as magnetic resonance imaging data. Among 42 patients with the diagnosis of isolated ATM, 12 (29%) were subsequently diagnosed with MS over a median follow-up period of 7.7 years. Univariately, MS converters were younger (32 years [25–39] vs. 42 years [31–50], p = 0.032), had a lower CSF/serum albumin ratio (29 [24–35] vs 37 [27–52], p = 0.037), lower CSF total protein (4.5 [2.8–4.8] vs. 5.5 [3.4–8.5], p = 0.023) and a higher proportion of CSF-specific oligoclonal bands (OCB; 83% vs. 30%, p = 0.002). In the multivariate regression analysis, the presence of CSF-specific OCB emerged as the sole predictive factor of subsequent MS diagnosis (OR: 14.42, 95% CI 1.39 to 149.48, p = 0.03). In a collective of 42 patients with isolated ATM and an MS conversion rate of nearly 30%, the only but highly predictive factor were CSF-specific OCB. This emphasizes the significance of conducting timely CSF analysis in such patients and underscores the need for tailored monitoring and follow-up strategies in this specific group.

Abstract Fabry disease (FD) constitutes a rare, X-linked lysosomal storage disorder affecting multiple organ systems, most notably heart, kidneys, and the central nervous system. Neurofilament light chains (NfL) have emerged as a prime candidate for a body fluid biomarker reflecting neuro-axonal injury. We aimed to evaluate its addition to the diagnostic and monitoring armamentarium in FD. Serum NfL concentrations (sNfL) were measured in 50 people with FD (PwFD) and 30 healthy control subjects (HC) using the Simoa© technology, followed by calculation of Z-scores adjusted for age and body mass index. In addition, clinical disease severity in PwFD was measured using the FOS-MSSI (Fabry outcome study – Mainz severity score index), which comprises clinical and paraclinical parameters. PwFD show elevated sNfL Z-scores compared to HC (PwFD: 1.12 [SD 1.5], HC: 0.01 [SD 1.2], p

# Background Oxygen is critical to the prevention of hypoxemia-induced morbidity and mortality; yet, access remains inadequate in most low- and middle-income countries despite billions of dollars spent over decades to increase supply. We present a new method for supplemental oxygen delivery whereby the OXFO System (OXFO Corporation, Boston, MA, USA) converts pressurized oxygen to ambient pressure for patient inhalation on demand at a fixed concentration across fluctuations in respiratory rate or tidal volume. This study's primary aims were to examine the oxygen volume savings and test the non-inferiority of mean peripheral oxygen saturation (S~pO2~) with the OXFO System (OXFO Condition) compared to conventional continuous flow (Standard Condition) in a clinical population of oxygen-dependent hospitalized adults. # Methods We conducted a non-inferiority, single-visit, randomized, crossover design. A total of 20 subjects were randomized to receive either OXFO Condition or Standard Condition first. Subjects were administered oxygen for 20 minutes during each condition after oxygen was titrated to target therapeutic S~pO2~. A one-sample t-test was performed to compare the mean ratio of oxygen volume dispensed (OXFO Condition/Standard Condition) with 100%. A paired t-test for non-inferiority was used to test the hypothesis that the mean S~pO2~ for OXFO Condition is no worse than 2.8% lower (absolute difference) than the mean S~pO2~ for Standard Condition. # Results Nineteen subjects were included in the analyses. When considering the dispensing of oxygen as a ratio (OXFO Condition / Standard Condition) for each subject, the mean was 7.7% (standard deviation(SD)=5.4%; range=0-20%) and this was significantly different from 100% (*P*\

Introduction Patients with Multiple Sclerosis (pwMS) treated with anti-CD20 (cluster of differentiation) monoclonal antibodies (mAbs) such as ocrelizumab (OCR) and ofatumumab (OFA) show a reduction mainly of B-lymphocytes, but also other lymphocyte subsets can be affected by these treatments. There is limited data on differences between lymphocyte subset counts of pwMS after treatment initiation with OCR or OFA. Objective To compare lymphocyte subset counts after treatment initiation in pwMS treated with OCR and OFA. Methods We analyzed 22 pwMS initiated on OFA and 56 sex-, age- and MS course matched pwMS initiated on OCR from 2 prospectively collected observational MS databases (Bern [n: OFA 14, OCR 44] and Vienna [n: OFA 8, OCR 12]) statistically comparing lymphocyte subset counts (Mann Whitney Test). Results We found that pwMS treated with OCR showed a stronger reduction of CD20 B-lymphocytes ( P = .001), and a trend towards lower counts of CD8 + T cells ( P = .056) compared to pwMS treated with OFA, whereas reduction of total lymphocyte, CD4 + lymphocyte and NK cell count was equally distributed between both treatments. Conclusion Different effects on lymphocyte subpopulations appear to be present in pwMS after treatment initiation with different anti-CD20 mAbs. Further studies are needed to determine potential effects on anti-CD20 treatment efficacy as well as treatment associated risks such as failed vaccinations and infections.

BackgroundRecent studies proposed cellular immunoprofiling as a surrogate for predicting treatment response and/or stratifying the occurrence of adverse events (AEs) in persons with multiple sclerosis (pwMS). However, applicability in real-world circumstances is not sufficiently addressed.ObjectiveWe aimed to explore whether standard routine clinical leukocyte phenotyping before treatment initiation could help stratify patients according to treatment response or AEs in a real-world MS cohort.MethodsIn this retrospective study, 150 pwMS were included, who had been newly initiated on a disease-modifying drug (DMD) and had been assessed for standard immunophenotyping before DMD initiation (baseline) and at least once during the following year. Multivariate models were used to assess an association of immune subsets and the association between immune cell profiles regarding treatment response and AEs.ResultsWe found that the composition of T cell subsets was associated with relapse activity, as an increased proportion of CD8+ lymphocytes at baseline indicated a higher likelihood of subsequent relapse (about 9% per 1% increase in CD8+ proportion of all CD3+ cells). This was particularly driven by patients receiving anti-CD20 therapy, where also EDSS worsening was associated with a higher number of CD8+ cells at baseline (3% increase per 10 cells). In the overall cohort, an increase in the proportion of NK cells was associated with a higher risk of EDSS worsening (5% per 1% increase). Occurrence of AEs was associated with a higher percentage of T cells and a lower number of percentual NKT cells at baseline.ConclusionImmune cell profiles are associated with treatment response and the occurrence of AEs in pwMS. Hence, immunophenotyping may serve as a valuable biomarker to enable individually tailored treatment strategies in pwMS.

Abstract Critical illness polyneuropathy (CIP) is a frequent and underdiagnosed phenomenon among intensive care unit patients. The lipophilic nature of neuronal synapses may result in the association of low serum cholesterol levels with a higher rate of CIP development. We aimed to investigate this issue in critically ill patients. All cases diagnosed with CIP in our tertiary care hospital between 2013 and 2017 were 1:1 matched with controls without the condition by age, sex, and ICD diagnoses. The main risk factors examined were the differences in change between initial and minimum serum total cholesterol levels, and minimum serum total cholesterol levels between matched pairs. Other predictors were serum markers of acute inflammation. We included 67 cases and 67 controls (134 critically ill patients, 49% female, 46% medical). Serum total cholesterol levels decreased more profoundly in cases than controls (median: −74 (IQR −115 to −24) vs. −39 (IQR −82 to −4), median difference: −28, 95% CI [−51, −5]), mg/dl). Minimum serum total cholesterol levels were lower in the cases (median difference: −24, 95% CI [−39, −9], mg/dl). We found significant median differences across matched pairs in maximum serum C-reactive protein (8.9, 95% CI [4.6, 13.2], mg/dl), minimum albumin (−4.2, 95% CI [−6.7, −1.7], g/l), decrease in albumin (−3.9, 95% CI [−7.6, −0.2], g/l), and lowest cholinesterase levels (−0.72, 95% CI [−1.05, −0.39], U/l). Subsequently, more pronounced decreases in serum total cholesterol levels and lower minimum total cholesterol levels during critical care unit hospitalizations may be a risk factor for CIP.

Abstract Objective Assessing severity of antibody‐mediated encephalitis (AE) or paraneoplastic encephalitis (PE) requires valid and reliable scores to guide treatment decisions and predict outcome both in clinical routine and studies. We aimed to validate the prognostic value of the clinical assessment scale in autoimmune encephalitis (CASE) and the anti‐NMDAR‐encephalitis one‐year functional status (NEOS) score in patients suffering from AE and PE in a large monocentric cohort. Methods We retrospectively applied the CASE and NEOS score to patients with definite AE and PE treated at a tertiary hospital. Correlations were established between the CASE and NEOS score and the modified Rankin scale (mRs). Multivariable analyses were calculated to identify predictors of outcome. Results Thirty‐four patients (27 AE, 7 PE) were included. Correlations between mRS and CASE score were strongest in patients with AE compared to PE at all intervals, but in the subgroups (LGI1, NMDAR, GAD, miscellaneous surface antibodies, PE) the correlation was strongest in the interval after baseline. Patients with AE seemed to display better outcomes compared to PE, which was underlined by multivariable analysis. Improvement was mostly observed within 6–12 months after disease onset, after which little or no further improvement was noted with some exception for two patients with anti‐NMDARE who recovered substantially even after 12 months of treatment. The NEOS score significantly predicted the outcome at last follow‐up in patients with AE with a sensitivity of 79% at a cut‐off value of 2 points (AUC 0.79, 95% CI 0.58–0.99, p = 0.04). Interpretation The CASE and NEOS score are suitable supplementary tools in addition to the mRS for capturing diverse symptoms, for grading and monitoring symptom severity.

El traumatismo cervical por arma cortopunzante es poco frecuente; sin embargo, por el gran interés clínico, puede dar lugar a complicaciones muy importantes, como asfixia, hemorragia masiva e incluso la muerte, sobre todo porque el 10 % de las lesiones traumáticas afectan a la región cervical (zona 1), la cual, por contener órganos y paquetes vasculares importantes, presenta una mortalidad del 1 al 7 %. De esta manera, se presenta el caso clínico de un paciente femenino de 90 años, con demencia senil, un cuadro clínico de 1 hora de evolución, con herida en región cervical derecha por objeto cortopunzante, con sangrado y dolor local, aparentemente por autolesión. La paciente fue sometida a cirugía para retiro de objeto cortopunzante y manejo en unidad de terapia intensiva (UTI) para monitorización, presentando una evolución optima y egresando al tercer día; posteriormente fue dada de alta a domicilio en buen estado general. VIDEO CORTO Y COMENTARIOS

Objetivos. Caracterizar la evolución del síndrome post-COVID-19 en Cochabamba-Bolivia, 2020-2021. Métodos. Estudio prospectivo, observacional y analítico. La muestra estuvo compuesta por 62 pacientes encuestados con COVID-19. Se pesquisó la gravedad y persistencia de los síntomas. Se aplicó el test exacto de Fisher, el cálculo del coeficiente n, la prueba de Kruskal-Wallis, la U de Mann-Whitney, además de la regresión logística binaria. Resultados. La media de edad fue de 34,2 ± 11,6 años; la disnea se presentó en el 45 % y tos con 42 %; dolor precordial con 30 %; astenia y mialgias con 29 %; ansiedad y depresión con 47 %, alteración de la memoria y concentración con 24 %; factor de riesgo predominante de la obesidad en el 11 %. La evolución de los síntomas fue por más de 10 días en un 48 %; se hospitalizaron entre 1 a 7 días en el 23 % de casos; se observó una disminución del desempeño laboral en el 34 %, de la calidad de vida en el 23 % y afectación económica en el 58 %. La persistencia de los síntomas se presentó en el 50 %, en correlación con la hospitalización, disminución de la calidad de vida y enfermedad de base (p < 0,05); además, se obtuvo un OR: 4,87, IC 95 % (1,54-17,2) para cuadros moderados y un OR: 4,42, IC 95 % (1,28-17,6) para la hospitalización en la persistencia de síntomas. Conclusiones. Sobresale la presencia de pacientes jóvenes, cuadros leves, moderados y sintomatología variada. La persistencia de síntomas se relacionó con la hospitalización y los cuadros moderados; podemos sugerir al síndrome COVID-19 post agudo y el síndrome COVID-19 crónico (< y > de 12 semanas), como definiciones tentativas, empero aún nos faltan más estudios al respecto

Abstract Background The diagnostic and pathophysiological relevance of antibodies to aquaporin-4 (AQP4-Ab) in patients with neuromyelitis optica spectrum disorders (NMOSD) has been intensively studied. However, little is known so far about the clinical impact of AQP4-Ab seropositivity. Objective To analyse systematically the clinical and paraclinical features associated with NMO spectrum disorders in Caucasians in a stratified fashion according to the patients' AQP4-Ab serostatus. Methods Retrospective study of 175 Caucasian patients (AQP4-Ab positive in 78.3%). Results Seropositive patients were found to be predominantly female (p < 0.0003), to more often have signs of co-existing autoimmunity (p < 0.00001), and to experience more severe clinical attacks. A visual acuity of ≤ 0.1 during acute optic neuritis (ON) attacks was more frequent among seropositives (p < 0.002). Similarly, motor symptoms were more common in seropositive patients, the median Medical Research Council scale (MRC) grade worse, and MRC grades ≤ 2 more frequent, in particular if patients met the 2006 revised criteria (p < 0.005, p < 0.006 and p < 0.01, respectively), the total spinal cord lesion load was higher (p < 0.006), and lesions ≥ 6 vertebral segments as well as entire spinal cord involvement more frequent (p < 0.003 and p < 0.043). By contrast, bilateral ON at onset was more common in seronegatives (p < 0.007), as was simultaneous ON and myelitis (p < 0.001); accordingly, the time to diagnosis of NMO was shorter in the seronegative group (p < 0.029). The course of disease was more often monophasic in seronegatives (p < 0.008). Seropositives and seronegatives did not differ significantly with regard to age at onset, time to relapse, annualized relapse rates, outcome from relapse (complete, partial, no recovery), annualized EDSS increase, mortality rate, supratentorial brain lesions, brainstem lesions, history of carcinoma, frequency of preceding infections, oligoclonal bands, or CSF pleocytosis. Both the time to relapse and the time to diagnosis was longer if the disease started with ON (p < 0.002 and p < 0.013). Motor symptoms or tetraparesis at first myelitis and > 1 myelitis attacks in the first year were identified as possible predictors of a worse outcome. Conclusion This study provides an overview of the clinical and paraclinical features of NMOSD in Caucasians and demonstrates a number of distinct disease characteristics in seropositive and seronegative patients.

Abstract Background In 70-80% of cases, neuromyelitis optica (NMO) is associated with highly specific serum auto-antibodies to aquaporin-4 (termed AQP4-Ab or NMO-IgG). Recent evidence strongly suggests that AQP4-Ab are directly involved in the immunopathogenesis of NMO. Objective To assess the frequency, syndrome specificity, diagnostic relevance, and origin of cerebrospinal fluid (CSF) AQP4-Ab in patients with NMO spectrum disorders (NMOSD). Methods 87 CSF samples from 37 patients with NMOSD and 42 controls with other neurological diseases were tested for AQP4-Ab in a cell based assay using recombinant human AQP4. Twenty-three paired CSF and serum samples from AQP4-Ab seropositive NMOSD patients were further analysed for intrathecal IgG synthesis to AQP4. Results AQP4-Ab were detectable in 68% of CSF samples from AQP4-Ab seropositive patients with NMOSD, but in none of the CSF samples from AQP4-Ab seronegative patients with NMOSD and in none of the control samples. Acute disease relapse within 30 days prior to lumbar puncture, AQP4-Ab serum titres >1:250, and blood-CSF barrier dysfunction, but not treatment status, predicted CSF AQP4-Ab positivity. A positive AQP4-specific antibody index was present in 1/23 samples analysed. Conclusions AQP4-Ab are detectable in the CSF of most patients with NMOSD, mainly during relapse, and are highly specific for this condition. In the cohort analysed in this study, testing for CSF AQP4-Ab did not improve the sensitivity and specificity of the current diagnostic criteria for NMO. The substantial lack of intrathecal AQP4-Ab synthesis in patients with NMOSD may reflect the unique localisation of the target antigen at the blood brain barrier, and is important for our understanding of the immunopathogenesis of the disease.

Summary: Background: X-linked adrenoleukodystrophy (X-ALD) is highly variable, ranging from slowly progressive adrenomyeloneuropathy to severe brain demyelination and inflammation (cerebral ALD, CALD) affecting males with childhood peak onset. Risk models integrating blood-based biomarkers to indicate CALD onset, enabling timely interventions, are lacking. Therefore, we evaluated the prognostic value of blood biomarkers in addition to current neuroimaging predictors for early detection of CALD. Methods: We measured blood biomarkers in a retrospective, male CALD risk-assessment cohort consisting of 134 X-ALD patients and 66 controls and in a phenotype-blinded validation set (25 X-ALD boys, 4–13 years) using Simoa®and Luminex® technologies. Findings: Among 25 biomarkers indicating axonal damage, astrocye/microglia activation, or immune-cell recruitment, neurofilament light chain (NfL) had the highest prognostic value for early indication of childhood/adolescent CALD. A plasma NfL cut-off level of 8.33 pg/mL, determined in the assessment cohort, correctly discriminated CALD with an accuracy of 96% [95% CI: 80–100] in the validation group. Multivariable logistic regression models revealed that combining NfL with GFAP or cytokines/chemokines (IL-15, IL-12p40, CXCL8, CCL11, CCL22, and IL-4) that were significantly elevated in CALD vs healthy controls had no additional benefit for detecting neuroinflammation. Some cytokines/chemokines were elevated only in childhood/adolescent CALD and already upregulated in asymptomatic X-ALD children (IL-15, IL-12p40, and CCL7). In adults, NfL levels distinguished CALD but were lower than in childhood/adolescent CALD patients with similar (MRI) lesion severity. Blood GFAP did not differentiate CALD from non-inflammatory X-ALD. Interpretation: Biomarker-based risk prediction with a plasma NfL cut-off value of 8.33 pg/mL, determined by ROC analysis, indicates CALD onset with high sensitivity and specificity in childhood X-ALD patients. A specific pro-inflammatory cytokine/chemokine profile in asymptomatic X-ALD boys may indicate a primed, immanent inflammatory state aligning with peak onset of CALD. Age-related differences in biomarker levels in adult vs childhood CALD patients warrants caution in predicting onset and progression of CALD in adults. Further evaluations are needed to assess clinical utility of the NfL cut-off for risk prognosis of CALD onset. Funding: Austrian Science Fund, European Leukodystrophy Association.

Background: Epileptic seizures can occur throughout the course of multiple sclerosis (MS) and are associated with increasing disability progression over time. However, there are no data on whether epileptic seizures at the onset of MS also lead to increasing disability. Objective: To examine disease progression over time for MS patients with epileptic seizures at onset. Methods: We analyzed the data of 30,713 patients on the German Multiple Sclerosis Register in a case–control study for more than 15 years. MS patients with seizures at onset were further divided into subgroups with polysymptomatic and monosymptomatic onset to assess the impact of additional symptoms on disease progression. Results: A total of 46 patients had seizures as onset symptoms. Expanded Disability Status Scale (EDSS) within the first year was lower in the group with seizures at onset compared to controls (0.75 versus 1.6, p

We describe the case of a 44-year-old male patient with a longstanding history of microhematuria and mildly impaired kidney function (CKD G2A1). The family history disclosed three females who also had microhematuria. Genetic testing by whole exome sequencing revealed two novel variants in COL4A4 (NM_000092.5: c.1181G>T, NP_000083.3: p.Gly394Val, heterozygous, likely pathogenic; Alport syndrome, OMIM# 141200, 203780) and GLA (NM_000169.3: c.460A>G, NP_000160.1: p.Ile154Val, hemizygous, variant of uncertain significance; Fabry disease, OMIM# 301500), respectively. Extensive phenotyping revealed no biochemical or clinical evidence for the presence of Fabry disease. Thus, the GLA c.460A>G, p.Ile154Val, is to be classified as a benign variant, whereas the COL4A4 c.1181G>T, p.Gly394Val confirms the diagnosis of autosomal dominant Alport syndrome in this patient.

Elevated levels of saturated very long-chain fatty acids (VLCFAs) in cell membranes and secreted lipoparticles have been associated with neurotoxicity and, therefore, require tight regulation. Excessive VLCFAs are imported into peroxisomes for degradation by β-oxidation. Impaired VLCFA catabolism due to primary or secondary peroxisomal alterations is featured in neurodegenerative and neuroinflammatory disorders such as X-linked adrenoleukodystrophy and multiple sclerosis (MS). Here, we identified that healthy human macrophages upregulate the peroxisomal genes involved in β-oxidation during myelin phagocytosis and pro-inflammatory activation, and that this response is impaired in peripheral macrophages and phagocytes in brain white matter lesions in MS patients. The pharmacological targeting of VLCFA metabolism and peroxisomes in innate immune cells could be favorable in the context of neuroinflammation and neurodegeneration. We previously identified the epigenetic histone deacetylase (HDAC) inhibitors entinostat and vorinostat to enhance VLCFA degradation and pro-regenerative macrophage polarization. However, adverse side effects currently limit their use in chronic neuroinflammation. Here, we focused on tefinostat, a monocyte/macrophage-selective HDAC inhibitor that has shown reduced toxicity in clinical trials. By using a gene expression analysis, peroxisomal β-oxidation assay, and live imaging of primary human macrophages, we assessed the efficacy of tefinostat in modulating VLCFA metabolism, phagocytosis, chemotaxis, and immune function. Our results revealed the significant stimulation of VLCFA degradation with the upregulation of genes involved in peroxisomal β-oxidation and interference with immune cell recruitment; however, tefinostat was less potent than the class I HDAC-selective inhibitor entinostat in promoting a regenerative macrophage phenotype. Further research is needed to fully explore the potential of class I HDAC inhibition and downstream targets in the context of neuroinflammation.

Objective: To investigate the metabolic pattern of different types of iron accumulation in multiple sclerosis (MS) lesions, and compare metabolic alterations within and at the periphery of lesions and newly emerging lesions in vivo according to iron deposition. Methods: 7 T MR spectroscopic imaging and susceptibility-weighted imaging was performed in 31 patients with relapsing-remitting MS (16 female/15 male; mean age, 36.9 ± 10.3 years). Mean metabolic ratios of four neuro-metabolites were calculated for regions of interest (ROI) of normal appearing white matter (NAWM), “non-iron” (lesion without iron accumulation on SWI), and three distinct types of iron-laden lesions (“rim”: distinct rim-shaped iron accumulation; “area”: iron deposition across the entire lesions; “transition”: transition between “area” and “rim” accumulation shape), and for lesion layers of “non-iron” and “rim” lesions. Furthermore, newly emerging “non-iron” and “iron” lesions were compared longitudinally, as measured before their appearance and one year later. Results: Thirty-nine of 75 iron-containing lesions showed no distinct paramagnetic rim. Of these, “area” lesions exhibited a 65% higher mIns/tNAA (p = 0.035) than “rim” lesions. Comparing lesion layers of both “non-iron” and “rim” lesions, a steeper metabolic gradient of mIns/tNAA (“non-iron” +15%, “rim” +40%) and tNAA/tCr (“non-iron” −15%, “rim” −35%) was found in “iron” lesions, with the lesion core showing +22% higher mIns/tNAA (p = 0.005) and –23% lower tNAA/tCr (p = 0.048) in “iron” compared to “non-iron” lesions. In newly emerging lesions, 18 of 39 showed iron accumulation, with the drop in tNAA/tCr after lesion formation remaining significantly lower compared to pre-lesional tissue over time in “iron” lesions (year 0: p = 0.013, year 1: p = 0.041) as opposed to “non-iron” lesions (year 0: p = 0.022, year 1: p = 0.231). Conclusion: 7 T MRSI allows in vivo characterization of different iron accumulation types each presenting with a distinct metabolic profile. Furthermore, the larger extent of neuronal damage in lesions with a distinct iron rim was reconfirmed via reduced tNAA/tCr concentrations, but with metabolic differences in lesion development between (non)-iron-containing lesions. This highlights the ability of MRSI to further investigate different types of iron accumulation and suggests possible implications for disease monitoring.