Hydrogen Sulfide Modulates Astrocytic Toxicity in Mouse Spinal Cord Cultures: Implications for Amyotrophic Lateral Sclerosis

Hydrogen sulfide (H2S), a known inhibitor of the electron transport chain, is endogenously produced in the periphery as well as in the central nervous system, where is mainly generated by glial cells. It affects, as a cellular signaling molecule, many different biochemical processes. In the central nervous system, depending on its concentration, it can be protective or damaging to neurons. In the study, we have demonstrated, in a primary mouse spinal cord cultures, that it is particularly harmful to motor neurons, is produced by glial cells, and is stimulated by inflammation. However, its role on glial cells, especially astrocytes, is still under-investigated. The present study was designed to evaluate the impact of H2S on astrocytes and their phenotypic heterogeneity, together with the functionality and homeostasis of mitochondria in primary spinal cord cultures. We found that H2S modulates astrocytes' morphological changes and their phenotypic transformation, exerts toxic properties by decreasing ATP production and the mitochondrial respiration rate, disturbs mitochondrial depolarization, and alters the energetic metabolism. These results further support the hypothesis that H2S is a toxic mediator, mainly released by astrocytes, possibly acting as an autocrine factor toward astrocytes, and probably involved in the non-cell autonomous mechanisms leading to motor neuron death.

Physical exercise in amyotrophic lateral sclerosis: a potential co-adjuvant therapeutic option to counteract disease progression

Amyotrophic lateral sclerosis (ALS) is a fatal disorder characterized by the selective degeneration of upper and lower motor neurons, leading to progressive muscle weakness and atrophy. The mean survival time is two to five years. Although the hunt for drugs has greatly advanced over the past decade, no cure is available for ALS yet. The role of intense physical activity in the etiology of ALS has been debated for several decades without reaching a clear conclusion. The benefits of organized physical activity on fitness and mental health have been widely described. Indeed, by acting on specific mechanisms, physical activity can influence the physiology of several chronic conditions. It was shown to improve skeletal muscle metabolism and regeneration, neurogenesis, mitochondrial biogenesis, and antioxidant defense. Interestingly, all these pathways are involved in ALS pathology. This review will provide a broad overview of the effect of different exercise protocols on the onset and progression of ALS, both in humans and in animal models. Furthermore, we will discuss challenges and opportunities to exploit physiological responses of imposed exercise training for therapeutic purposes.

Perioperative pain management after scapular tip free flap harvesting for head and neck reconstruction using mini-catheters to inject the local anesthetic

PURPOSE

Although functional and esthetic results after the use of a scapular tip free flap (STFF) in head and neck reconstruction, and the related donor-site morbidity, have been extensively described, data regarding acute postoperative donor-site pain management are lacking. Purpose of this study is to explore the use of mini-catheters to administer local anesthetics for donor-site pain management after reconstruction using STFF.

METHODS

Patients who underwent head and neck reconstruction using a STFF were prospectively enrolled and, through a perineural catheter placed in the donor site during the surgical procedure, a bolus of chirochaine was injected before the patient regained consciousness and at 8, 16, and 24 h postoperatively. Before and 40 min after each dose administration, donor-site pain on a numerical rating scale (NRS; 0-10) was evaluated.

RESULTS

Study population consisted of 20 patients (40-88 years). At 8 h, the pain scores before and after the injection were 0-10 (mean 3.35) and 0-5 (mean 1.25), respectively. At 16 h, the pain scores before and after the injection were 0-8 (mean 2.55) and 0-4 (mean 0.55), respectively. At 24 h, the pain scores before and after the injection were 0-8 (mean 1.30) and 0-4 (mean 0.30), respectively.

CONCLUSION

Statistical analysis confirmed a significant difference between the pain scores before and after administration at 8, 16, and 24 h (p < 0.001, p < 0.001, and p = 0.003, respectively). Mini-catheters for local anesthetic administration represent an effective strategy for pain control after STFF harvesting for head and neck reconstruction.

Endurance exercise has a negative impact on the onset of SOD1-G93A ALS in female mice and affects the entire skeletal muscle-motor neuron axis

Background

Amyotrophic lateral sclerosis (ALS) is a fatal neuromuscular disease characterized by the degeneration of motor neurons that leads to muscle wasting and atrophy. Epidemiological and experimental evidence suggests a causal relationship between ALS and physical activity (PA). However, the impact of PA on motor neuron loss and sarcopenia is still debated, probably because of the heterogeneity and intensities of the proposed exercises. With this study, we aimed to clarify the effect of intense endurance exercise on the onset and progression of ALS in the SOD1-G93A mouse model.

Methods

We randomly selected four groups of twelve 35-day-old female mice. SOD1-G93A and WT mice underwent intense endurance training on a motorized treadmill for 8 weeks, 5 days a week. During the training, we measured muscle strength, weight, and motor skills and compared them with the corresponding sedentary groups to define the disease onset. At the end of the eighth week, we analyzed the skeletal muscle-motor neuron axis by histological and molecular techniques.

Results

Intense endurance exercise anticipates the onset of the disease by 1 week (age of the onset: trained SOD1-G93A = 63.17 ± 2.25 days old; sedentary SOD1-G93A = 70.75 ± 2.45 days old). In SOD1-G93A mice, intense endurance exercise hastens the muscular switch to a more oxidative phenotype and worsens the denervation process by dismantling neuromuscular junctions in the tibialis anterior, enhancing the Wallerian degeneration in the sciatic nerve, and promoting motor neuron loss in the spinal cord. The training exacerbates neuroinflammation, causing immune cell infiltration in the sciatic nerve and a faster activation of astrocytes and microglia in the spinal cord.

Conclusion

Intense endurance exercise, acting on skeletal muscles, worsens the pathological hallmarks of ALS, such as denervation and neuroinflammation, brings the onset forward, and accelerates the progression of the disease. Our findings show the potentiality of skeletal muscle as a target for both prognostic and therapeutic strategies; the preservation of skeletal muscle health by specific intervention could counteract the dying-back process and protect motor neurons from death. The physiological characteristics and accessibility of skeletal muscle further enhance its appeal as a therapeutic target.

Dysregulation of alternative splicing underlies synaptic defects in familial amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis (ALS) is an incurable neurodegenerative disease characterized by the degeneration of upper and lower motor neurons, progressive wasting and paralysis of voluntary muscles. A hallmark of ALS is the frequent nuclear loss and cytoplasmic accumulation of RNA binding proteins (RBPs) in motor neurons (MN), which leads to aberrant alternative splicing regulation. However, whether altered splicing patterns are also present in familial models of ALS without mutations in RBP-encoding genes has not been investigated yet. Herein, we found that altered splicing of synaptic genes is a common trait of familial ALS MNs. Similar deregulation was also observed in hSOD1G93A MN-like cells. In silico analysis identified the potential regulators of these pre-mRNAs, including the RBP Sam68. Immunofluorescence analysis and biochemical fractionation experiments revealed that Sam68 accumulates in the cytoplasmic insoluble ribonucleoprotein fraction of MN. Remarkably, the synaptic splicing events deregulated in ALS MNs were also affected in Sam68-/- spinal cords. Recombinant expression of Sam68 protein was sufficient to rescue these splicing changes in ALS hSOD1G93A MN-like cells. Hence, our study highlights an aberrant function of Sam68, which leads to splicing changes in synaptic genes and may contribute to the MN phenotype that characterizes ALS.

Different Chronic Stress Paradigms Converge on Endogenous TDP43 Cleavage and Aggregation

The TAR-DNA binding protein (TDP43) is a nuclear protein whose cytoplasmic inclusions are hallmarks of Amyotrophic Lateral Sclerosis (ALS). Acute stress in cells causes TDP43 mobilization to the cytoplasm and its aggregation through different routes. Although acute stress elicits a strong phenotype, is far from recapitulating the years-long aggregation process. We applied different chronic stress protocols and described TDP43 aggregation in a human neuroblastoma cell line by combining solubility assays, thioflavin-based microscopy and flow cytometry. This approach allowed us to detect, for the first time to our knowledge in vitro, the formation of 25 kDa C-terminal fragment of TDP43, a pathogenic hallmark of ALS. Our results indicate that chronic stress, compared to the more common acute stress paradigm, better recapitulates the cell biology of TDP43 proteinopathies. Moreover, we optimized a protocol for the detection of bona fide prions in living cells, suggesting that TDP43 may form amyloids as a stress response.

Butyrate prevents visceral adipose tissue inflammation and metabolic alterations in a Friedreich's ataxia mouse model

Friedreich's ataxia (FA) is a neurodegenerative disease resulting from a mutation in the FXN gene, leading to mitochondrial frataxin deficiency. FA patients exhibit increased visceral adiposity, inflammation, and heightened diabetes risk, negatively affecting prognosis. We investigated visceral white adipose tissue (vWAT) in a murine model (KIKO) to understand its role in FA-related metabolic complications. RNA-seq analysis revealed altered expression of inflammation, angiogenesis, and fibrosis genes. Diabetes-like traits, including larger adipocytes, immune cell infiltration, and increased lactate production, were observed in vWAT. FXN downregulation in cultured adipocytes mirrored vWAT diabetes-like features, showing metabolic shifts toward glycolysis and lactate production. Metagenomic analysis indicated a reduction in fecal butyrate-producing bacteria, known to exert antidiabetic effects. A butyrate-enriched diet restrained vWAT abnormalities and mitigated diabetes features in KIKO mice. Our work emphasizes the role of vWAT in FA-related metabolic issues and suggests butyrate as a safe and promising adjunct for FA management.

An impaired splicing program underlies differentiation defects in hSOD1G93A neural progenitor cells

Amyotrophic lateral sclerosis (ALS) is an adult devastating neurodegenerative disease characterized by the loss of upper and lower motor neurons (MNs), resulting in progressive paralysis and death. Genetic animal models of ALS have highlighted dysregulation of synaptic structure and function as a pathogenic feature of ALS-onset and progression. Alternative pre-mRNA splicing (AS), which allows expansion of the coding power of genomes by generating multiple transcript isoforms from each gene, is widely associated with synapse formation and functional specification. Deciphering the link between aberrant splicing regulation and pathogenic features of ALS could pave the ground for novel therapeutic opportunities. Herein, we found that neural progenitor cells (NPCs) derived from the hSOD1G93A mouse model of ALS displayed increased proliferation and propensity to differentiate into neurons. In parallel, hSOD1G93A NPCs showed impaired splicing patterns in synaptic genes, which could contribute to the observed phenotype. Remarkably, master splicing regulators of the switch from stemness to neural differentiation are de-regulated in hSOD1G93A NPCs, thus impacting the differentiation program. Our data indicate that hSOD1G93A mutation impacts on neurogenesis by increasing the NPC pool in the developing mouse cortex and affecting their intrinsic properties, through the establishment of a specific splicing program.

Immune-mediated myogenesis and acetylcholine receptor clustering promote a slow disease progression in ALS mouse models

BACKGROUND

Amyotrophic lateral sclerosis (ALS) is a heterogeneous disease in terms of onset and progression rate. This may account for therapeutic clinical trial failure. Transgenic SOD1G93A mice on C57 or 129Sv background have a slow and fast disease progression rate, mimicking the variability observed in patients. Based on evidence inferring the active influence of skeletal muscle on ALS pathogenesis, we explored whether dysregulation in hindlimb skeletal muscle reflects the phenotypic difference between the two mouse models.

METHODS

Ex vivo immunohistochemical, biochemical, and biomolecular methodologies, together with in vivo electrophysiology and in vitro approaches on primary cells, were used to afford a comparative and longitudinal analysis of gastrocnemius medialis between fast- and slow-progressing ALS mice.

RESULTS

We reported that slow-progressing mice counteracted muscle denervation atrophy by increasing acetylcholine receptor clustering, enhancing evoked currents, and preserving compound muscle action potential. This matched with prompt and sustained myogenesis, likely triggered by an early inflammatory response switching the infiltrated macrophages towards a M2 pro-regenerative phenotype. Conversely, upon denervation, fast-progressing mice failed to promptly activate a compensatory muscle response, exhibiting a rapidly progressive deterioration of muscle force.

CONCLUSIONS

Our findings further pinpoint the pivotal role of skeletal muscle in ALS, providing new insights into underestimated disease mechanisms occurring at the periphery and providing useful (diagnostic, prognostic, and mechanistic) information to facilitate the translation of cost-effective therapeutic strategies from the laboratory to the clinic.

SerpinE1 drives a cell-autonomous pathogenic signaling in Hutchinson-Gilford progeria syndrome

Hutchinson-Gilford progeria syndrome (HGPS) is a rare, fatal disease caused by Lamin A mutation, leading to altered nuclear architecture, loss of peripheral heterochromatin and deregulated gene expression. HGPS patients eventually die by coronary artery disease and cardiovascular alterations. Yet, how deregulated transcriptional networks at the cellular level impact on the systemic disease phenotype is currently unclear. A genome-wide analysis of gene expression in cultures of primary HGPS fibroblasts identified SerpinE1, also known as Plasminogen Activator Inhibitor (PAI-1), as central gene that propels a cell-autonomous pathogenic signaling from the altered nuclear lamina. Indeed, siRNA-mediated downregulation and pharmacological inhibition of SerpinE1 by TM5441 could revert key pathological features of HGPS in patient-derived fibroblasts, including re-activation of cell cycle progression, reduced DNA damage signaling, decreased expression of pro-fibrotic genes and recovery of mitochondrial defects. These effects were accompanied by the correction of nuclear abnormalities. These data point to SerpinE1 as a novel potential effector and target for therapeutic interventions in HGPS pathogenesis.

Proteome data of neuroblastoma cells overexpressing Neuroglobin

In this article, we present data on the proteome of human neuroblastoma cells stably overexpressing Neuroglobin (NGB). The neuroprotective role of NGB is clearly established, nevertheless the related mechanistic processes, which are dependent on NGB overexpression, are not known. To address this question, we performed shotgun label-free quantification (LFQ) proteomics using an SH-SY5Y cell model of neuroblastoma that overexpresses an NGB-FLAG construct, and wild type cells transfected with an empty vector as control (CTRL). The proteomes from six biological samples per condition were digested using the S-Trap sample preparation followed by LC-MS/MS analysis with a LTQ-Orbitrap XL mass spectrometer. The quantitative analysis was performed using the LFQ algorithm of MaxQuant, leading to 1654 correctly quantified proteins over 2580 identified proteins. Finally, the statistic comparison of the two analyzed groups within Perseus platform identified 178 differential proteins (107 up- and 71 down-regulated). In addition, multivariate statistical analysis was carried out using MetaboAnalyst 5.0 software. MS proteomics data are available via ProteomeXchange with the dataset identifier PXD029012.

Impact of the chronic disease self-management program (CDSMP) on self-perceived frailty condition: the EU-EFFICHRONIC project

Introduction:

The Chronic Disease Self-Management Program (CDSMP) improves self-efficacy and health outcomes in people with chronic diseases. In the context of the EFFICHRONIC project, we evaluated the efficacy of CDSMP in relieving frailty, as assessed by the self-administered version of Multidimensional Prognostic Index (SELFY-MPI), identifying also potential predictors of better response over 6-month follow-up.

Methods:

The SELFY-MPI explores mobility, basal and instrumental activities of daily living (Barthel mobility, ADL, IADL), cognition (Test Your Memory-TYM Test), nutrition (Mini Nutritional Assessment-Short Form-MNA-SF), comorbidities, medications, and socio-economic conditions (social-familiar evaluation scale-SFES). Participants were stratified in three groups according to the 6-month change of SELFY-MPI: those who improved after CDSMP (Δ SELFY-MPI < 0), those who remained unchanged (Δ SELFY-MPI = 0), and those who worsened (Δ SELFY-MPI > 0). Multivariable logistic regression was modeled to identify predictors of SELFY-MPI improvement.

Results:

Among 270 participants (mean age = 61.45 years, range = 26–93 years; females = 78.1%) a benefit from CDSMP intervention, in terms of decrease in the SELFY-MPI score, was observed in 32.6% of subjects. SELFY-MPI improvement was found in participants with higher number of comorbidities (1–2 chronic diseases: adjusted odd ratio (aOR)=2.38, 95% confidence interval (CI) =1.01, 5.58; ⩾ 3 chronic diseases: aOR = 3.34, 95% CI = 1.25, 8.90 vs no chronic disease), poorer cognitive performance (TYM ⩽ 42: aOR = 2.41, 95% CI = 1.12, 5.19 vs TYM > 42) or higher risk of malnutrition (MNA-SF ⩽ 11: aOR = 6.11, 95% CI = 3.15, 11.83 vs MNA-SF > 11).

Conclusion:

These findings suggest that the CDSMP intervention contributes to decreasing the self-perceived severity of frailty (SELFY-MPI score) in more vulnerable participants with several chronic diseases and lower cognitive performance and nutritional status.

Repurposing of Trimetazidine for Amyotrophic Lateral Sclerosis: a study in SOD1G93A mice

Background and Purpose

Amyotrophic lateral sclerosis (ALS), a neurodegenerative disease characterized by the degeneration of upper and lower motor neurons, progressive wasting and paralysis of voluntary muscles and is currently incurable. Although considered to be a pure motor neuron disease, increasing evidence indicates that the sole protection of motor neurons by a single targeted drug is not sufficient to improve the pathological phenotype. We therefore evaluated the therapeutic potential of the multi‐target drug used to treatment of coronary artery disease, trimetazidine, in SOD1^G93A mice.

Experimental Approach

As a metabolic modulator, trimetazidine improves glucose metabolism. Furthermore, trimetazidine enhances mitochondrial metabolism and promotes nerve regeneration, exerting an anti‐inflammatory and antioxidant effect. We orally treated SOD1^G93A mice with trimetazidine, solubilized in drinking water at a dose of 20 mg kg⁻¹, from disease onset. We assessed the impact of trimetazidine on disease progression by studying metabolic parameters, grip strength and histological alterations in skeletal muscle, peripheral nerves and the spinal cord.

Key Results

Trimetazidine administration delays motor function decline, improves muscle performance and metabolism, and significantly extends overall survival of SOD1^G93A mice (increased median survival of 16 days and 12.5 days for male and female respectively). Moreover, trimetazidine prevents the degeneration of neuromuscular junctions, attenuates motor neuron loss and reduces neuroinflammation in the spinal cord and in peripheral nerves.

Conclusion and Implications

In SOD1^G93A mice, therapeutic effect of trimetazidine is underpinned by its action on mitochondrial function in skeletal muscle and spinal cord.

Microglia Morphological Changes in the Motor Cortex of hSOD1G93A Transgenic ALS Mice

Amyotrophic lateral sclerosis (ALS) is characterized by the progressive degeneration of spinal motor neurons as well as corticospinal (CSN) large pyramidal neurons within cortex layer V. An intense microglia immune response has been associated with both upper and lower motor neuron degeneration in ALS patients, whereas microgliosis occurrence in the motor cortex of hSOD1^G93A mice—the best characterized model of this disease—is not clear and remains under debate. Since the impact of microglia cells in the neuronal environment seems to be crucial for both the initiation and the progression of the disease, here we analyzed the motor cortex of hSOD1^G93A mice at the onset of symptoms by the immunolabeling of Iba1/TMEM119 double positive cells and confocal microscopy. By means of Sholl analysis, we were able to identify and quantify the presence of presumably activated Iba1/TMEM119-positive microglia cells with shorter and thicker processes as compared to the normal surveilling and more ramified microglia present in WT cortices. We strongly believe that being able to analyze microglia activation in the motor cortex of hSOD1^G93A mice is of great importance for defining the timing and the extent of microglia involvement in CSN degeneration and for the identification of the initiation stages of this disease.

Protein Aggregation Landscape in Neurodegenerative Diseases: Clinical Relevance and Future Applications

Intrinsic disorder is a natural feature of polypeptide chains, resulting in the lack of a defined three-dimensional structure. Conformational changes in intrinsically disordered regions of a protein lead to unstable β-sheet enriched intermediates, which are stabilized by intermolecular interactions with other β-sheet enriched molecules, producing stable proteinaceous aggregates. Upon misfolding, several pathways may be undertaken depending on the composition of the amino acidic string and the surrounding environment, leading to different structures. Accumulating evidence is suggesting that the conformational state of a protein may initiate signalling pathways involved both in pathology and physiology. In this review, we will summarize the heterogeneity of structures that are produced from intrinsically disordered protein domains and highlight the routes that lead to the formation of physiological liquid droplets as well as pathogenic aggregates. The most common proteins found in aggregates in neurodegenerative diseases and their structural variability will be addressed. We will further evaluate the clinical relevance and future applications of the study of the structural heterogeneity of protein aggregates, which may aid the understanding of the phenotypic diversity observed in neurodegenerative disorders.

Skeletal Muscle in ALS: An Unappreciated Therapeutic Opportunity?

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disorder characterized by the selective degeneration of upper and lower motor neurons and by the progressive weakness and paralysis of voluntary muscles. Despite intense research efforts and numerous clinical trials, it is still an incurable disease. ALS had long been considered a pure motor neuron disease; however, recent studies have shown that motor neuron protection is not sufficient to prevent the course of the disease since the dismantlement of neuromuscular junctions occurs before motor neuron degeneration. Skeletal muscle alterations have been described in the early stages of the disease, and they seem to be mainly involved in the "dying back" phenomenon of motor neurons and metabolic dysfunctions. In recent years, skeletal muscles have been considered crucial not only for the etiology of ALS but also for its treatment. Here, we review clinical and preclinical studies that targeted skeletal muscles and discuss the different approaches, including pharmacological interventions, supplements or diets, genetic modifications, and training programs.

3D planning of ear prosthesis and navigated flapless surgery for craniofacial implants: A pilot study

New 3D digital technologies can be applied to implant-supported ear prostheses to restore anatomical structures damaged by cancer, dysplasia, or trauma. However, several factors influence the accuracy of implant positioning using a cranial template. This pilot study describes an innovative navigated flapless surgery for craniofacial implants, prosthetically guided by 3D planning of the ear prosthesis. Laser surface scanning of the face allowed for mapping of the healthy ear onto the defect site, and projection of the volume and position of the final prosthesis. The projected ear volume was superimposed on the skull bone image obtained by cone-beam computed tomography (CBCT), performed with the navigation system marker plate positioned in the patient's mouth. The craniofacial implants were fitted optimally to the ear prosthesis. After system calibration, real-time navigated implant placement based on the virtual planning was performed with minimally invasive flapless surgery under local anesthesia. After 3 months of healing, digital impressions of the implants were made, and the digital manufacturing workflow was completed to manufacture the ear prosthesis anchored to the craniofacial implants. The proposed digital method facilitated implant positioning during flapless surgery, improving the ear prosthesis manufacturing process and reducing operation time, patient morbidity, and related costs. This protocol avoids the need for a reference tool fixed in the cranial bone, as is usually required for maxillofacial surgery, and confirmed that surgical navigation is useful for guiding the insertion of craniofacial implants during flapless surgery.

Altered skeletal muscle glucose-fatty acid flux in amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis is characterized by the degeneration of upper and lower motor neurons, yet an increasing number of studies in both mouse models and patients with amyotrophic lateral sclerosis suggest that altered metabolic homeostasis is also a feature of disease. Pre-clinical and clinical studies have shown that modulation of energy balance can be beneficial in amyotrophic lateral sclerosis. However, the capacity to target specific metabolic pathways or mechanisms requires detailed understanding of metabolic dysregulation in amyotrophic lateral sclerosis. Here, using the superoxide dismutase 1, glycine to alanine substitution at amino acid 93 (SOD1^G93A) mouse model of amyotrophic lateral sclerosis, we demonstrate that an increase in whole-body metabolism occurs at a time when glycolytic muscle exhibits an increased dependence on fatty acid oxidation. Using myotubes derived from muscle of amyotrophic lateral sclerosis patients, we also show that increased dependence on fatty acid oxidation is associated with increased whole-body energy expenditure. In the present study, increased fatty acid oxidation was associated with slower disease progression. However, within the patient cohort, there was considerable heterogeneity in whole-body metabolism and fuel oxidation profiles. Thus, future studies that decipher specific metabolic changes at an individual patient level are essential for the development of treatments that aim to target metabolic pathways in amyotrophic lateral sclerosis.

Skeletal-Muscle Metabolic Reprogramming in ALS-SOD1G93A Mice Predates Disease Onset and Is A Promising Therapeutic Target

Patients with ALS show, in addition to the loss of motor neurons in the spinal cord, brainstem, and cerebral cortex, an abnormal depletion of energy stores alongside hypermetabolism. In this study, we show that bioenergetic defects and muscle remodeling occur in skeletal muscle of the SOD1^G93A mouse model of ALS mice prior to disease onset and before the activation of muscle denervation markers, respectively. These changes in muscle physiology were followed by an increase in energy expenditure unrelated to physical activity. Finally, chronic treatment of SOD1^G93A mice with Ranolazine, an FDA-approved inhibitor of fatty acid β-oxidation, led to a decrease in energy expenditure in symptomatic SOD1^G93A mice, and this occurred in parallel with a robust, albeit temporary, recovery of the pathological phenotype.

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Metabolic switch use occurs early in the skeletal muscle of SOD1^G93A mice

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Mitochondrial impairment precedes locomotor deficits and evokes catabolic pathways

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Sarcolipin upregulation in presymptomatic SOD1^G93A mice precedes hypermetabolism

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Pharmacological modulation of hypermetabolism improves locomotor performance

P752 Mitral regurgitation in patients with severe aortic stenosis: role of valvular calcification in the persistence of mitral regurgitation after aortic valve replacement

Introduction

mitral regurgitation is often associated with severe aortic stenosis but the indications for its correction at the time of aortic valve surgery are still unclear. Despite the indication for mitral valve repair or replacement in the case of severe secondary mitral regurgitation, many patients are left untreated. This is due to the common belief that secondary mitral regurgitation mostly improves after the aortic valve is treated.

Purpose

the aim of the study is to investigate the prevalence and distribution of mitral calcifications, their role in the development of mitral regurgitation and in its reduction after aortic valve replacement.

Methods

we reviewed all patient’s records who underwent aortic valve replacement for aortic stenosis at our institution from 12/2014 to 12/2016. Pre and post-operative echocardiograms were reviewed by experienced echocardiographer. Patients were then divided into 4 categories (functional, mild, moderate and severe calcification) on the basis of the presence, distribuition and severity of calcification on the mitral apparatus.

Results

at the end 651 patients were collected and analyzed. Mean age was 74yo. 334 (51,4%) of them were males. Most patients (63,1%) had only mild mitral regurgitation but 147 (22,6%) of them had moderate or severe mitral regurgitation. The presences of moderate or severe calcification of the mitral apparatus resulted to be a risk factor for the presence of mitral regurgitation associated with aortic stenosis as shown in Table 1. After surgical aortic valve replacement less than 21% of the patients showed a reduction of the degree of mitral regurgitation. We found no statistical difference between groups about mitral regurgitation changes after aortic valve replacement.

Conclusions

Mitral regurgitation is a common finding in patients with severe aortic stenosis and it’s prevalence is higher in patients with mitral calcifications. Few patients, however showed a reduction in the degree of mitral regurgitation after surgical aortic valve replacement with no difference related to the severity of annular or leaflets calcifications.

TABLE 1 Logistic regression for the presence of mitral regurgitation Mitral Regurgitation Change after Aortic Valve Replacement CALCIFICATION DEGREE OR C.I. 95% p Reduced p Unchanged p Increased p Functional 53(21%) 176(71%) 18(7%) Mild 1.244571 0.81 - 1.93 0.32 28(20%) 0.86 105(76%) 0.43 6(4%) 0.34 Moderate 1.637297 1.05 - 2.56 0.03* 25(17%) 0.41 109(76%) 0.34 9(6%) 0.86 Severe 2.369245 1.46 - 3.85 &lt;0.01* 29(25%) 0.48 78(68%) 0.67 7(6%) 0.86 OR= Odds Ratio; C.I.=Confidence Interval; Functional= no calcification; Mild, Moderate and Severe= degree of mitral annular and leaflets calcifications.