Magnetic Resonance Imaging Confirmed Olfactory Bulb Reduction in Long COVID-19: Literature Review and Case Series

An altered sense of smell and taste was recognized as one of the most characteristic symptoms of coronavirus infection disease (COVID-19). Despite most patients experiencing a complete functional resolution, there is a 21.3% prevalence of persistent alteration at 12 months after infection. To date, magnetic resonance imaging (MRI) findings in these patients have been variable and not clearly defined. We aimed to clarify radiological alterations of olfactory pathways in patients with long COVID-19 characterized by olfactory dysfunction. A comprehensive review of the English literature was performed by analyzing relevant papers about this topic. A case series was presented: all patients underwent complete otorhinolaryngology evaluation including the Sniffin’ Sticks battery test. A previous diagnosis of SARS-CoV-2 infection was confirmed by positive swabs. The MRIs were acquired using a 3.0T MR scanner with a standardized protocol for olfactory tract analysis. Images were first analysed by a dedicated neuroradiologist and subsequently reviewed and compared with the previous available MRIs. The review of the literature retrieved 25 studies; most cases of olfactory dysfunction more than 3 months after SARS-CoV-2 infection showed olfactory bulb (OB) reduction. Patients in the personal case series had asymmetry and a reduction in the volume of the OB. This evidence was strengthened by the comparison with a previous MRI, where the OBs were normal. The results preliminarily confirmed OB reduction in cases of long COVID-19 with an altered sense of smell. Further studies are needed to clarify the epidemiology, pathophysiology and prognosis

Brown and Beige Adipose Tissue and Aging

Across aging, adipose tissue (AT) changes its quantity and distribution: AT becomes dysfunctional with an increase in production of inflammatory peptides, a decline of those with anti-inflammatory activity and infiltration of macrophages. Adipose organ dysfunction may lead to age-related metabolic alterations. Aging is characterized by an increase in adiposity and a decline in brown adipose tissue (BAT) depots and activity, and UCP1 expression. There are many possible links to age-associated involution of BAT, including the loss of mitochondrial function, impairment of the sympathetic nervous system, age-induced alteration of brown adipogenic stem/progenitor cell function and changes in endocrine signals. Aging is also associated with a reduction in beige adipocyte formation. Beige adipocytes are known to differentiate from a sub-population of progenitors resident in white adipose tissue (WAT); a defective ability of progenitor cells to proliferate and differentiate has been hypothesized with aging. The loss of beige adipocytes with age may be caused by changes in trophic factors in the adipose tissue microenvironment, which regulate progenitor cell proliferation and differentiation. This review focuses on possible mechanisms involved in the reduction of BAT and beige activity with aging, along with possible targets for age-related metabolic disease therapy

Arterial Stiffness, Subendocardial Impairment, and 30-Day Readmission in Heart Failure Older Patients

Arterial stiffness and subendocardial perfusion impairment may play a significant role in heart failure (HF) outcomes. The aim of the study was to examine the main predictors of 30-day readmission in geriatric patients, hospitalized with HF, explore hemodynamical parameters, arterial stiffness indexes, and subendocardial viability ratio (SEVR). In total, 41 hospitalized patients, affected by HF, were included; they underwent clinical evaluation, routine laboratory testing, and echocardiography. At the time of admission, after the achievement of clinical stability (defined as switching from intravenous to oral diuretic therapy), and at discharge, arterial tonometry was performed to evaluate carotid-femoral pulse wave velocity (PWVcf) and SEVR (then corrected for hemoglobin concentration and oxygen saturation). Through the evaluations, a significant progressive decrease in PWVcf was described (17.79 ± 4.49, 13.54 ± 4.54, and 9.94 ± 3.73 m/s), even after adjustment for age, gender, mean arterial pressure (MAP) variation, and left ventricular ejection fraction (LVEF). A significant improvement was registered for both SEVR (83.48 ± 24.43, 97.94 ± 26.84, and 113.29 ± 38.02) and corrected SEVR (12.74 ± 4.69, 15.71 ± 5.30, and 18.55 ± 6.66) values, and it was still significant when adjusted for age, gender, MAP variation, and LVEF. After discharge, 26.8% of patients were readmitted within 30 days. In a multivariate binary logistic regression analysis, PWVcf at discharge was the only predictor of 30-day readmission (odds ratio [OR] 1.957, 95% CI 1.112-3.443). In conclusion, medical therapy seems to improve arterial stiffness and subendocardial perfusion in geriatric patients hospitalized with heart failure. Furthermore, PWVcf is a valid predictor of 30-day readmission. Its feasibility in clinical practice may provide an instrument to detect patients with HF at high risk of rehospitalization

The impact of chemical short-range order on the thermophysical properties of medium- and high-entropy alloys

The unusual behavior observed in the coefficient of thermal expansion and specific heat capacity of CrFeNi, CoCrNi, and CoCrFeNi medium/high-entropy alloys is commonly referred to as the K-state effect. It is shown to be independent of the Curie temperature, as demonstrated by temperature-dependent magnetic moment measurements. CoCrFeNi alloy is chosen for detailed characterization; potential reasons for the K-state effect such as texture, recrystallization, and second-phase precipitation are ruled out. An examination of the electronic structure indicates the formation of a pseudo-gap in the Density of States, which suggests a specific chemical interaction between Ni and Cr atoms upon alloying. Hybrid Monte Carlo/Molecular Dynamic (MC/MD) simulations indicate the presence of non-negligible chemical short-range order (CSRO). Local lattice distortions are shown to be negligible, although deviations around Cr and Ni elements from those expected in a fully disordered structure are experimentally observed by X-ray absorption spectroscopy. The determined bonding distances are in good agreement with MC/MD calculations. A mechanism is proposed to explain the anomalies and calorimetric experiments and their results are used to validate the mechanism

Exploratory Study on Chemosensory Event-Related Potentials in Long COVID-19 and Mild Cognitive Impairment: A Common Pathway?

People affected by the Long COVID-19 (LC) syndrome often show clinical manifestations that are similar to those observed in patients with mild cognitive impairments (MCI), such as olfactory dysfunction (OD), brain fog, and cognitive and attentional diseases. This study aimed to investigate the chemosensory-evoked related potentials (CSERP) in LC and MCI to understand if there is a common pathway for the similarity of symptoms associated with these disorders. Eighteen LC patients (mean age 53; s.d. = 7), 12 patients diagnosed with MCI (mean age 67; s.d. = 6), and 10 healthy control subjects (mean age 66; s.d. = 5, 7) were recruited for this exploratory study. All of them performed a chemosensory event-related potentials (CSERP) task with the administration of trigeminal stimulations (e.g., the odorants cinnamaldehyde and eucalyptus). Study results highlighted that MCI and LC showed reduced N1 amplitude, particularly in the left frontoparietal network, involved in working memory and attentional deficits, and a reduction of P3 latency in LC. This study lays the foundations for evaluating aspects of LC as a process that could trigger long-term functional alterations, and CSERPs could be considered valid biomarkers for assessing the progress of OD and an indicator of other impairments (e.g., attentional and cognitive impairments), as they occur in MCI

Vegan Diet Advice Might Benefit Liver Enzymes in Nonalcoholic Fatty Liver Disease: an Open Observational Pilot Study.

Background and Aims: The Western diet is rich in saturated fats, refined sugars and meat consistent with a high-energy load and secondary risk of increased metabolic diseases including nonalcoholic fatty liver disease (NAFLD). However, no data are available on potential benefit of vegan diets in NAFLD and/or nonalcoholic steatohepatitis (NASH). We aimed to study prospectively the effect of a vegan diet, excluding all animal products on liver chemistry in a group of consecutive NAFLD patients. Methods: This was a prospective, pilot study run on 40 consecutive patients affected by NAFLD. Eight subjects refused to join the study for poor diet palatability, leaving 32 patients (19 males, mean age 50 years), with abnormal measures of liver function who agreed to adhere to a vegan diet for six months. The caloric intake was tailored by the dietitian to obtain a weight loss ≥5% of body weight in overweight patients [body-mass index (BMI) ≥25] and ranged from 1500 Kcal to 1800 Kcal. Patients were contacted monthly by phone to reinforce diet and lifestyle advice and were seen at the gastrointestinal clinic when doubtful about diet advice. Results: At six-month follow-up, 6 subjects did not attend the clinic leaving only 26 patients for data analysis. Initial anthropometric values were mean weight 78 kg (range 52-95), mean body mass index (BMI) 26.8 Kg/m2 (range 20.3-31.2). Liver function tests showed mean ALT value 99 U/L (SD±45), mean AST value 54 U/L (SD±44), mean GGT value 160 U/L (SD±122), pre-treatment. After six months mean body weight was 73 Kg (range 52-87), mean BMI was 25.2 Kg/m2 (range 20.3-29.7) (p<0.001 compared to baseline for both parameters). Liver enzymes improved to a mean of ALT value 36 U/L (SD±21), AST value 27 U/L (SD±10) and GGT value 55 U/L (SD±57), respectively (p<0.001 compared to baseline for all enzymes). Normalization of liver function tests as a whole was observed in 20/26 patients (76.9%). A loss of ≥ 5% of body weight was observed in 12 patients (46.1%), but it did not correlate with the normalization of liver function tests (p=0.5). Conclusions: Our data provide preliminary evidence of improved liver enzymes in NAFLD patients with a strict vegan diet and although our study sample is limited, decreased body weight did not seem critical to the outcome

Voice parameters in children with cochlear implants: a systematic review and meta-analysis

ABSTRACT: Introduction: An intact auditory system is essential for the development and maintenance of voice quality and speech prosody. On the contrary hearing loss affects the adjustments and appropriate use of organs involved in speech and voice production. Spectro-acoustic voice parameters have been valuated in CI users, and the authors of previous systematic reviews on the topic concluded that preliminary Fundamental Frequency seemed the most reliable parameter to evaluate voice alterations in adult CI users. The main aim of this systematic review and meta-analysis was to clarify the vocal parameters and prosodic alterations of speech in pediatric CI users. Materials and methods: The protocol of the systematic review was registered on the PROSPERO database International prospective register of systematic reviews. We conducted a search of the English literature published in the period between January 1st 2005 and April 1st 2022 on the Pubmed and Scopus databases. A meta-analysis was conducted to compare the values of voice acoustic parameters in CI users and nonhearing-impaired controls. The analysis was conducted using the standardized mean difference as the outcome measure. A random-effects model was fitted to the data. Results: A total of 1334 articles were initially evaluated using title and abstract screening. After applying inclusion/exclusion criteria, 20 articles were considered suitable for this review. The age of the cases ranged between 25 to 132 months at examination. The most studied parameters were F0, Jitter, Shimmer and Harmoni Noise Ratio (HNR); other parameters were seldom reported. A total of 11 studies were included in the meta-analysis of F0, with the majority of estimates being positive (75%); the estimated average standardized mean difference based on the random-effects model was 0.3033 (95% CI: 0.0605 to 0.5462; p = 0.0144). For Jitter (0.2229; 95% CI: -0.1862 to 0.7986; p = 0.2229) and shimmer (0.2540; 95% CI: -0.1404 to 0.6485; p = 0.2068) there was a trend toward positive values without reaching statistical significance. Discussion and conclusions: This meta-analysis confirmed that higher F0 values have been observed in the pediatric population of CI users compared to age-matched normal hearing volunteers, whereas the parameters of voice noise were not significantly different between cases and controls. Prosodic aspects of language need further investigations. In longitudinal contexts, prolonged auditory experience with CI has brought voice parameters closer to the norm. Following the available evidence, we stress the utility of inclusion of vocal acoustic analysis in the clinical evaluation and follow-up of CI patients to optimize the rehabilitation process of pediatric patients with hearing loss

Functional and Structural Brain Damage in Friedreich's Ataxia

Friedreich's ataxia (FRDA) is a rare hereditary neurodegenerative disorder caused by a GAA repeat expansion in the FXN gene. There is still no cure or quantitative biomarkers reliaby correlating with the progression rate and disease severity. Investigation of functional and structural alterations characterizing white (WM) and gray matter (GM) in FRDA are needed prerequisite to monitor progression and response to treatment. Here we report the results of a multimodal cross-sectional MRI study of FRDA including Voxel-Based Morphometry (VBM), diffusion-tensor imaging (DTI), functional MRI (fMRI), and a correlation analysis with clinical severity scores. Twenty-one early-onset FRDA patients and 18 age-matched healthy controls (HCs) were imaged at 3T. All patients underwent a complete cognitive and clinical assessment with ataxia scales. VBM analysis showed GM volume reduction in FRDA compared to HCs bilaterally in lobules V, VI, VIII (L&gt;R), as well as in the crus of cerebellum, posterior lobe of the vermis, in the flocculi and in the left tonsil. Voxel-wise DTI analysis showed a diffuse fractional anisotropy reduction and mean, radial, axial (AD) diffusivity increase in both infratentorial and supratentorial WM. ROI-based analysis confirmed the results showing differences of the same DTI metrics in cortico-spinal-tracts, forceps major, corpus callosum, posterior thalamic radiations, cerebellar penduncles. Additionally, we observed increased AD in superior (SCP) and middle cerebellar peduncles. The WM findings correlated with age at onset (AAO), short-allelle GAA, and disease severity. The intragroup analysis of fMRI data from right-handed 14 FRDA and 15 HCs showed similar findings in both groups, including activation in M1, insula and superior cerebellar hemisphere (lobules V–VIII). Significant differences emerged only during the non-dominant hand movement, with HCs showing a stronger activation in the left superior cerebellar hemisphere compared to FRDA. Significant correlations were found between AAO and the fMRI activation in cerebellar anterior and posterior lobes, insula and temporal lobe. Our multimodal neuroimaging protocol suggests that MRI is a useful tool to document the extension of the neurological impairment in FRDA

Adipokines and arterial stiffness in the elderly

Introduction: The aim of this study was to evaluate the relationship between adipokines and arterial stiffness in a group of 85 elderly subjects and the role of leptin and adiponectin on subclinical vascular damage, defined by a PWV> 10 m/s. Methods: In each subject, we evaluated anthropometry, body composition by DXA (fat mass, fat mass%, lean mass), metabolic variables, leptin, adiponectin, systolic, diastolic, mean arterial pressure and pulse pressure (SBP, DBP, MAP, PP), carotid-femoral pulse wave velocity (cfPWV) and carotid-radial pulse wave velocity (crPWV). Results: In the study population, significant associations were observed between cfPWV and crPWV, age, SBP, MAP, waist circumference, fat body mass and leptin. The study population was subdivided in 2 subgroups according to adipokine patterns: group 1 included patients with high adiponectin and low leptin, and group 2 patients had high leptin and low adiponectin. SBP, PP, cfPWV were significantly higher in subjects with high leptin and low adiponectin (group 2). Even after adjustment for gender, fat mass%, MAP, HDL cholesterol and triglycerides, cfPWV was higher in group 2 than group 1. In a logistic binary regression on the entire population, considering subclinical vascular damage as a dependent variable and age, gender, MAP, fat mass%, triglycerides, HDL cholesterol and category of subjects with high leptin and low adiponectin as independent variables, MAP and category of subjects with high leptin and low adiponectin were significant predictors (OR, respectively, 1.09 and 3.61). Conclusion: In conclusion, in the elderly, the presence at the same time of high leptin levels and low adiponectin levels seems to have synergic effects on arterial stiffness