MODULAZIONE DEI FENOMENI DI SENESCENZA CELLULARE DI ADIPOCITI E PREADIPOCITI IN VITRO

L’invecchiamento è accompagnato da una complessa rete di processi biologici caratterizzati da uno stato infiammatorio cronico basale, a sua volta correlato allo sviluppo di patologie età-associate come: aterosclerosi, osteoartriti, Alzheimer, diabete di tipo 2. Una sempre più approfondita analisi del processo di senescenza tessutospecifico potrebbe consentire l’individuazione di target terapeutici utili a modulare il processo complessivo dell’invecchiamento stesso. L’invecchiamento è causa di declino delle funzionalità sistemiche e il tessuto adiposo è uno degli organi maggiormente colpiti in quanto subisce cambiamenti significativi che riguardano la quantità, la distribuzione, la composizione cellulare e l’attività endocrina, giocando un ruolo chiave nell’insorgenza di insulino-resistenza, di disfunzioni metaboliche e infiammazione sistemica. L’abbondanza del tessuto adiposo e le diverse funzioni da esso esercitate lo rendono un organo fondamentale per la comprensione della fisiologia dell’intero organismo. Tuttavia, i cambiamenti a cui è sottoposto durante il processo di invecchiamento sono solo in parte noti e oggetto di studio negli ultimi anni. È quindi fondamentale conoscere i processi molecolari che stanno alla base della fisiopatologia del tessuto adiposo e del suo invecchiamento in modo da poter individuare strategie terapeutiche per le malattie correlate all’invecchiamento. In questo studio, è stato messo a punto un modello cellulare di senescenza in vitro attraverso il trattamento con perossido di idrogeno (H2O2) in adipociti e preadipociti 3T3-L1 murini. Successivamente è stata valutata la potenziale attività senolitica della quercetina esaminandone l’effetto antiossidante e antinfiammatorio, cercando di individuarne il target molecolare.Aging is associated with pathological age-related processes as inflammatory low-grade state, atherosclerosis, Alzheimer's disease, type II diabetes and osteoarthritis diseases. A deep analysis of the tissue-specific senescence process could allow the identification of therapeutic targets to modulate the aging process itself. In this study, premature senescence model was developed in vitro through treatment with oxygen peroxide (H2O2) in murine 3T3-L1 preadipocytes before and after induction to mature adipocytes. H2O2 treated cells showed characteristic senescence-associated features including senescence-associated beta-galactosidase activity (SA-ß-gal), activation of reactive oxygen species (ROS) development of senescence-associated secretory phenotype (SASP), induction of cell cycle inhibitors P-21 as well as induction of pro-inflammatory transduction factor NFκB and a downregulation of deacetylase SIRT1. We found that stimulation with H2O2 results in an induction of miR-155-5p expression in preadipocytes and in mature adipocytes. The treatment with quercetin (20 μM) showed significant decrease in the number of ß-galactosidase positive cell along with the suppression of ROS, NFκB and SASP factor in both cell models. In addition, quercetin treatment also upregulated protein expression of SIRT1 and decreased miR-155-5p expression. These results suggest that quercetin acts as a potential senolytic agent in both preadipocytes and adipocytes cell models, inhibiting ROS production and proinflammatory miR-155-5p

Relationship between lipid droplets size and integrated optical density

Lipid accumulation is largely investigated due to its role in many human diseases. The attention is mainly focused on the lipid droplets (LDs), spherical cytoplasmic organelles which are devoted to the storage of the lipids. The amount of lipid content is often evaluated by measuring LDs size and/or the integrated optical density (IOD) in cultured cells. Both evaluations are directly associated to the lipid content and therefore they are correlated to each other, but a lack of theoretical relationship between size and IOD was observed in literature. Here we investigated the size-IOD relationship of LDs observed in microscopical images of cultured cells. The experimental data were obtained from immature and differentiated 3T3-L1 murine cells, which have been extensively used in studies on adipogenesis. A simple model based on the spherical shape of the LDs and the Lambert-Beer law, which describes the light absorption by an optical thick material, leads to a mathematical relationship. Despite only light rays\u2019 absorption was considered in the model, neglecting their scattering, a very good agreement between the theoretical curve and the experimental data was found. Moreover, a computational simulation corroborates the model indicating the validity of the mathematically theoretical relationship between size and IOD. The theoretical model could be used to calculate the absorption coefficient in the LDs population and it could be applied to seek for morphologically and functionally LDs subpopulations. The identification of LDs dynamic by measuring size and IOD could be related to different pathophysiological conditions and useful for understand cellular lipid-associated diseases

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

Obesity as a risk factor for unfavourable outcomes in critically ill patients affected by Covid 19

BACKGROUND AND AIMS: Recent studies show that obesity is a risk factor for hospital admission and for critical care need in patients with coronavirus disease 2019 (COVID-19). The aim was to determine whether obesity is a risk factor for unfavourable health outcomes in patients affected by COVID-19 admitted to ICU.METHODS AND RESULTS: 95 consecutive patients with COVID-19 (78 males and 18 females) were admitted to ICU and included in the study. Height, weight, BMI, Sequential Organ Failure Assessment (SOFA) and Acute Physiology and Chronic Health Evaluation II (APACHE II) scores, CRP, CPK, ICU and hospital length of stay and comorbidities were evaluated. Participants with obesity had a lower 28 day survival rate from ICU admission than normal weight subjects. Cox proportional hazard model-derived estimates, adjusted for age, gender and comorbidity, confirmed the results of the survival analysis (HR:5.30,95%C.I.1.26-22.34). Obese subjects showed longer hospital and ICU stay as compared with normal weight counterpart.Subjects with obesity showed significantly higher CRP and CPK levels than normal weight subjects.CONCLUSION: In individuals with obesity, careful management and prompt intervention in case of suspected SARS-CoV-2 infection is necessary to prevent the progression of the disease towards severe outcomes and the increase of hospital treatment costs

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

Effects of secukinumab on serum adipocytokines: preliminary data

Psoriatic arthritis (PsA) is a chronic inflammatory disease that affects joints, connective tissues and the axial skeleton. Metabolic syndrome is an independent risk factor for psoriasis (Pso) development and is associated with more severe forms of Pso. Adipocytokines are secreted by white adipose tissue and are thought to link obesity with the development of metabolic and cardiovascular diseases. Secukinumab is a new monoclonal antibody with a different mechanism of action. This antibody selectively binds to and neutralizes interleukin-17 (IL-17) and it has shown efficacy in the treatment of PsA. The aim of this study was to evaluate the possible interferences of secukinumab on different adipocytokines. We enrolled 28 patients with PsA, classified with the CASPAR criteria. Serum samples were stored at baseline and then at the first, the third and the sixth month of therapy. Resistin, chemerin, adiponectin and C-reactive protein (CRP) were dosed. When tested globally, none of the adipokine tested showed any statistically significant variation. However, when the male group was tested, both resistin and chemerin at M6 showed a significant decrease from baseline. CRP did not show any variation at any time point. Our study demonstrated that treatment with secukinumab has little influence on the levels of adipokines tested within the first six months of treatment even though it might exert different influence between males and females from a metabolic perspective. Further studies with greater numbers of patients are needed to determine whether these preliminary results have clinical relevance

Myocardial fibrosis and steatosis in patients with aortic stenosis: roles of myostatin and ceramides

Aortic stenosis (AS) involves progressive valve obstruction and a remodeling response of the left ventriculum (LV) with systolic and diastolic dysfunction. The roles of interstitial fibrosis and myocardial steatosis in LV dysfunction in AS have not been completely characterized. We enrolled 31 patients (19 women and 12 men) with severe AS undergoing elective aortic valve replacement. The subjects were clinically evaluated, and transthoracic echocardiography was performed pre-surgery. LV septal biopsies were obtained to assess fibrosis and apoptosis and fat deposition in myocytes (perilipin 5 (PLIN5)), or in the form of adipocytes within the heart (perilipin 1 (PLIN1)), the presence of ceramides and myostatin were assessed via immunohistochemistry. After BMI adjustment, we found a positive association between fibrosis and apoptotic cardiomyocytes, as well as fibrosis and the area covered by PLIN5. Apoptosis and PLIN5 were also significantly interrelated. LV fibrosis increased with a higher medium gradient (MG) and peak gradient (PG). Ceramides and myostatin levels were higher in patients within the higher MG and PG tertiles. In the linear regression analysis, increased fibrosis correlated with increased apoptosis and myostatin, independent from confounding factors. After adjustment for age and BMI, we found a positive relationship between PLIN5 and E/A and a negative correlation between septal S', global longitudinal strain (GLS), and fibrosis. Myostatin was inversely correlated with GLS and ejection fraction. Fibrosis and myocardial steatosis altogether contribute to ventricular dysfunction in severe AS. The association of myostatin and fibrosis with systolic dysfunction, as well as between myocardial steatosis and diastolic dysfunction, highlights potential therapeutic targets

Senescent adipocytes as potential effectors of muscle cells dysfunction: An in vitro model

Recently, there has been a growing body of evidence showing a negative effect of the white adipose tissue (WAT) dysfunction on the skeletal muscle function and quality. However, little is known about the effects of senescent adipocytes on muscle cells. Therefore, to explore potential mechanisms involved in age-related loss of muscle mass and function, we performed an in vitro experiment using conditioned medium obtained from cultures of mature and aged 3 T3-L1 adipocytes, as well as from cultures of dysfunctional adipocytes exposed to oxidative stress or high insulin doses, to treat C2C12 myocytes. The results from morphological measures indicated a significant decrease in diameter and fusion index of myotubes after treatment with medium of aged or stressed adipocytes. Aged and stressed adipocytes presented different morphological characteristics as well as a different gene expression profile of proinflammatory cytokines and ROS production. In myocytes treated with different adipocytes' conditioned media, we demonstrated a significant reduction of gene expression of myogenic differentiation markers as well as a significant increase of genes involved in atrophy. Finally, a significant reduction in protein synthesis as well as a significant increase of myostatin was found in muscle cells treated with medium of aged or stressed adipocytes compared to controls. In conclusion, these preliminary results suggest that aged adipocytes could influence negatively trophism, function and regenerative capacity of myocytes by a paracrine network of signaling

Sarcopenia: European consensus on definition and diagnosis: Report of the European Working Group on Sarcopenia in Older People

The European Working Group on Sarcopenia in Older People (EWGSOP) developed a practical clinical definition and consensus diagnostic criteria for age-related sarcopenia. EWGSOP included representatives from four participant organisations, i.e. the European Geriatric Medicine Society, the European Society for Clinical Nutrition and Metabolism, the International Association of Gerontology and Geriatrics—European Region and the International Association of Nutrition and Aging. These organisations endorsed the findings in the final document. The group met and addressed the following questions, using the medical literature to build evidence-based answers: (i) What is sarcopenia? (ii) What parameters define sarcopenia? (iii) What variables reflect these parameters, and what measurement tools and cut-off points can be used? (iv) How does sarcopenia relate to cachexia, frailty and sarcopenic obesity? For the diagnosis of sarcopenia, EWGSOP recommends using the presence of both low muscle mass + low muscle function (strength or performance). EWGSOP variously applies these characteristics to further define conceptual stages as ‘presarcopenia', ‘sarcopenia' and ‘severe sarcopenia'. EWGSOP reviewed a wide range of tools that can be used to measure the specific variables of muscle mass, muscle strength and physical performance. Our paper summarises currently available data defining sarcopenia cut-off points by age and gender; suggests an algorithm for sarcopenia case finding in older individuals based on measurements of gait speed, grip strength and muscle mass; and presents a list of suggested primary and secondary outcome domains for research. Once an operational definition of sarcopenia is adopted and included in the mainstream of comprehensive geriatric assessment, the next steps are to define the natural course of sarcopenia and to develop and define effective treatmen