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Background Opportunistic computed tomography (CT) bone density assessment using Hounsfield units (HU) is increasingly used. Body mass index (BMI) may influence dual-energy X-ray absorptiometry (DXA), computed tomography X-ray absorptiometry of the hip (CTXA), and CT attenuation values, potentially affecting HU thresholds and fracture discrimination. We quantified associations between BMI, femoral HU, hip T-scores, and prevalent fractures. Methods We retrospectively analyzed 600 consecutive patients (65.3 ± 14.1 years; 81% female; BMI 26.7 ± 6.5 kg/m²) who underwent CTXA hip assessment. Trabecular HU were measured on coronal CT images using a circular ROI in the femoral head and an irregular ROI in the proximal femur. BMI subgroups followed WHO categories. Spearman correlations (ρ) and linear regression analyses (R²) were performed. Multivariable linear and logistic regression models were adjusted for age and sex. Results BMI correlated positively with femoral HU and hip T-score (ρ = 0.46; p  < 0.001). In multivariable models, each 1 kg/m² increase in BMI was associated with higher HU values (+ 3.32 HU; 95% CI 2.61–4.02) and higher hip T-score (+ 0.081; 95% CI 0.064–0.098; p  < 0.001). Fracture prevalence decreased across BMI categories. HU values discriminated patients with and without hip fracture (AUC up to 0.99). Given the cross-sectional design, these values reflect discrimination within the study cohort rather than prospective predictive validity. No proximal femur fractures occurred above the osteoporosis threshold of 94.77 HU. Conclusions BMI was independently associated with CT attenuation and CTXA-derived bone density parameters and inversely associated with prevalent fractures in this cohort. BMI should be considered when interpreting opportunistic HU measurements and applying fixed thresholds.

Quantitative susceptibility mapping (QSM) and effective transverse relaxation rate (R2*) mapping are both highly sensitive to variations in brain iron content. Clinical Magnetic Resonance Imaging (MRI) studies report changes of susceptibilities and relaxation rates in various neurological diseases which are often equated with changes in regional brain iron content. However, these mentioned metrics lack specificity for iron, since they are also influenced by the presence of myelin. In this study, we assessed the extent to which QSM and R2* reflect iron concentration as well as histological iron and myelin intensities. Six unfixed human post-mortem brains were imaged in situ with a 7 T MRI scanner. After formalin fixation, the brains were sliced axially and punched. 671 tissue punches were subjected to ferrozine iron quantification. Subsequently, brain slices were embedded in paraffin, and histological double-hemispheric axial brain slices were stained for Luxol fast blue (myelin) and diaminobenzidine (DAB)-enhanced Turnbull blue (iron). 3331 regions of interest (ROIs) were drawn on the histological stainings to assess myelin and iron intensities, which were compared with MRI data in corresponding ROIs. QSM more closely reflected quantitative ferrozine iron values (r = 0.755 vs. 0.738), whereas R2* correlated better with iron staining intensities (r = 0.619 vs. 0.445). Myelin intensities correlated negatively with QSM (r = −0.352), indicating a diamagnetic effect of myelin on susceptibility. Myelin intensities were higher in the thalamus than in the basal ganglia. A significant relationship was nonetheless observed between quantitative iron values and QSM, confirming the applicability of the latter in this brain region for iron quantification. •Brain iron can be visualized using quantitative susceptibility (QSM) and R2* mapping.•Anatomical structures show different contributions of iron and myelin to QSM or R2*.•Iron and myelin have opposite effects on QSM throughout the human brain.•The relation between brain iron and myelin differs between anatomical structures.

A strong mechanistic link between the regulation of iron homeostasis and oxygen sensing is evident in the lung, where both systems must be properly controlled to maintain lung function. Imbalances in pulmonary iron homeostasis are frequently associated with respiratory diseases, such as chronic obstructive pulmonary disease and with lung cancer. However, the underlying mechanisms causing alterations in iron levels and the involvement of iron in the development of lung disorders are incompletely understood. Here, we review current knowledge about the regulation of pulmonary iron homeostasis, its functional importance, and the link between dysregulated iron levels and lung diseases. Gaining greater knowledge on how iron contributes to the pathogenesis of these diseases holds promise for future iron-related therapeutic strategies.

Multiple sclerosis (MS) is the most common autoimmune disease affecting the central nervous system. It is characterized by autoreactive T cells that induce demyelination and neuronal degradation. Treatment options are still limited and several MS medications need to be administered by parenteral application but are modestly effective. Oral active drugs such as fingolimod have been weighed down by safety concerns. Consequently, there is a demand for novel, especially orally active therapeutics. Nature offers an abundance of compounds for drug discovery. Recently, the circular plant peptide kalata B1 was shown to silence T-cell proliferation in vitro in an IL-2–dependent mechanism. Owing to this promising effect, we aimed to determine in vivo activity of the cyclotide [T20K]kalata B1 using the MS mouse model experimental autoimmune encephalomyelitis (EAE). Treatment of mice with the cyclotide resulted in a significant delay and diminished symptoms of EAE by oral administration. Cyclotide application substantially impeded disease progression and did not exhibit adverse effects. Inhibition of lymphocyte proliferation and the reduction of proinflammatory cytokines, in particular IL-2, distinguish the cyclotide from other marketed drugs. Considering their stable structural topology and oral activity, cyclotides are candidates as peptide therapeutics for pharmaceutical drug development for treatment of T-cell-mediated disorders.

Burn injuries elicit a unique and dynamic stress response which can lead to burn injury progression. Though neutrophils represent crucial players in the burn-induced immunological events, the dynamic secretion pattern and systemic levels of neutrophil-derived factors have not been investigated in detail so far. Serum levels of neutrophil elastase (NE), myeloperoxidase (MPO), citrullinated histone H3 (CitH3), and complement factor C3a were quantified in burn victims over 4 weeks post injury. Furthermore, the potential association with mortality, degree of burn injury, and inhalation trauma was evaluated. In addition, leukocyte, platelet, neutrophil, and lymphocyte counts were assessed. Lastly, we analyzed the association of neutrophil-derived factors with clinical severity scoring systems. Serum levels of NE, MPO, CitH3, and C3a were remarkably elevated in burn victims compared to healthy controls. Leukocyte and neutrophil counts were significantly increased on admission day and day 1, while relative lymphocytes were decreased in the first 7 days post burn trauma. Though neutrophil-derived factors did not predict mortality, patients suffering from 3rd degree burn injuries displayed increased CitH3 and NE levels. Accordingly, CitH3 and NE were elevated in cases with higher abbreviated burn severity indices (ABSI). Taken together, our data suggest a role for neutrophil activation and NETosis in burn injuries and burn injury progression. Targeting exacerbated neutrophil activation might represent a new therapeutic option for severe cases of burn injury.

Heart Failure (HF) is a major health and economic issue worldwide. HF-related expenses are largely driven by hospital admissions and re-admissions, many of which are potentially preventable. Current self-management programs, however, have failed to reduce hospital admissions. This may be explained by their low predictive power for decompensation and high adherence requirements. Slight alterations in the voice profile may allow to detect decompensation in HF patients at an earlier stage and reduce hospitalizations. This pilot study investigates the potential of voice as a digital biomarker to predict health status deterioration in HF patients. In a two-month longitudinal observational study, we collect voice samples and HF-related quality-of-life questionnaires from 35 stable HF patients. Patients use our developed study application installed on a tablet at home during the study period. From the collected data, we use signal processing to extract voice characteristics from the audio samples and associate them with the answers to the questionnaire data. The primary outcome will be the correlation between voice characteristics and HF-related quality-of-life health status. The study was reviewed and approved by the Cantonal Ethics Committee Zurich (BASEC ID:2022-00912). Results will be published in medical and technical peer-reviewed journals.

Fibroblast growth factor 23 (FGF23) is a major endocrine regulator of phosphate and 1,25 (OH)2 vitamin D3 metabolism and is mainly produced by osteocytes. Its production is upregulated by a variety of factors including 1,25 (OH)2 vitamin D3, high dietary phosphate intake, and parathyroid hormone (PTH). Recently, iron deficiency and hypoxia have been suggested as additional regulators of FGF23 and a role of erythropoietin (EPO) was shown. However, the regulation of FGF23 by EPO and the impact on phosphate and 1,25(OH)2 vitamin D3 are not completely understood. Here, we demonstrate that acute administration of recombinant human EPO (rhEPO) to healthy humans increases the C-terminal fragment of FGF23 (C-terminal FGF23) but not intact FGF23 (iFGF23). In mice, rhEPO stimulates acutely (24 h) C-terminal FGF23 but iFGF23 only after 4 days without effects on PTH and plasma phosphate. 1,25 (OH)2 D3 levels and αklotho expression in the kidney decrease after 4 days. rhEPO induced FGF23 mRNA in bone marrow but not in bone, with increased staining of FGF23 in CD71+ erythroid precursors in bone marrow. Chronic elevation of EPO in transgenic mice increases iFGF23. Finally, acute injections of recombinant FGF23 reduced renal EPO mRNA expression. Our data demonstrate stimulation of FGF23 levels in mice which impacts mostly on 1,25 (OH)2 vitamin D3 levels and metabolism. In humans, EPO is mostly associated with the C-terminal fragment of FGF23; in mice, EPO has a time-dependent effect on both FGF23 forms. EPO and FGF23 may form a feedback loop controlling and linking erythropoiesis and mineral metabolism.

The need for bone graft materials to fill bony voids or gaps that are not related to the intrinsic stability of the bone that arise due to trauma, tumors or osteolysis remains a clinically relevant and significant issue. The in vivo response of collagen-tricalcium phosphate bone graft substitutes was evaluated in a critical size cancellous defect model in skeletally mature rabbits. While the materials were chemically virtually identical, new bone formation, implant resorption and local in vivo responses were significantly different. Differences in the in vivo response may be due, in part, collagen source and processing which influences resorption profiles. Continued improvements in processing and manufacturing techniques of collagen-tricalcium phosphate bone graft substitutes can result in osteoconductive materials that support healing of critical size bone defects even in challenging pre-clinical models.

Heart failure (HF) is among the most prevalent health issues worldwide and is associated with high mortality. Adequate decongestion remain the main clinical challenge in HF management. Sodium glucose cotransporter-2 inhibitors (SGLT-2i) have been recently introduced as a new treatment option in patients with HF irrespective of left ventricular ejection fraction. Although the favorable effects of SGLT-2i are profoundly evident, the underlying mechanisms are not yet well understood. The aim of this study is to provide novel insights into the effects of dapagliflozin, a SGLT-2i with proven cardiovascular benefit, on blood volume profile and vascular function in HF patients who had a recent event of acute decompensated heart failure (ADHF). Eighty adult patients with diagnosis of de novo or chronic HF (NYHA class II-IV), clinically stabilized after an ADHF event and with preserved renal function, who were not on treatment with SGLT-2i, are aimed to be included. The patients are randomized with 1:1 allocation to either dapagliflozin 10 mg p.o. once daily or placebo in addition to guideline-directed medical therapy. The primary outcome is the mean change in plasma volume status (PVS) in the dapagliflozin group compared to placebo. PVS is assessed via optimized carbon monoxide rebreathing technique, a reliable and safe method to measure total hemoglobin mass and to estimate blood volume profile, i.e., blood volume, plasma volume and red blood cell volume. Secondary outcomes include differences between the two study groups regarding blood volume profile, micro- and macro-vascular function assessed by retinal vessel analysis and flow-mediated vasodilation, respectively, changes in body water distribution, quality of life, exercise capacity, echocardiographic and laboratory parameters. The study has been approved by the Cantonal Ethics Committee Zurich (BASEC-Nr.:2020-01920, Swissmedic-Nr.:2020DR4175) and has been registered at www.ClinicalTrials.gov‌ (NCT04869124). The results will be published in a peer-reviewed medical journal.

The myelin‐associated inhibitor Nogo‐A (Reticulon 4, RTN4) restricts axonal outgrowth, plasticity, and neural circuitry formation in experimental models of spinal cord injury (SCI) and is targeted in clinical interventions starting treatment within 4 weeks post‐SCI. Specifically, Nogo‐A expressed by oligodendroglia restricts compensatory neurite sprouting. To interrogate the hypothesis of an inducible, lesion reactive Nogo‐A expression over time, we analyzed the spatiotemporal Nogo‐A expression at the spinal lesion core (region of tissue necrosis and axonal damage/pruning) and perilesional rim (region of plasticity formation). Spinal cord specimens of SCI subjects (n = 22) were compared to neuropathologically unaltered controls (n = 9). Nogo‐A expression was investigated ranging from acute (0–3 days), early subacute (4–21 days), late subacute (22–90 days) to early chronic–chronic (91 days to 1.5 years after SCI) stages after SCI. Nogo‐A expression in controls is confined to motoneurons in the anterior horn and to oligodendrocytes in gray and white matter. After SCI, the number of Nogo‐A+ and TPPP/p25+ oligodendrocytes (i) inclined at the organizing perilesional rim specifically, (ii) increased further over time, and (iii) peaked at chronic stages after SCI. By contrast, at the lesion core, the number of Nogo‐A+ and TPPP/p25+ oligodendrocytes did not increase. Increasing numbers of Nogo‐A+ oligodendrocytes coincided with oligodendrogenesis corroborated by Nogo‐A coexpression of Ki67+, TPPP/p25+ proliferating oligodendrocytes. Nogo‐A oligodendrocyte expression emerges at perilesional (plasticity) regions over time and suggests an extended therapeutical window for anti‐Nogo‐A pathway targeting interventions beyond 4 weeks in patients after SCI. Nogo‐A oligodendrocytes expression emerges at perilesional regions over time and suggests an extended therapeutical window for anti‐Nogo‐A pathway trageting interventrions beyond four weeks in patients after spinal cord injury.