Bottom Effect in Atomic Force Microscopy Nanomechanics

In this work, the influence of the rigid substrate on the determination of the sample Young''s modulus, the so-called bottom-effect artifact, is demonstrated by an atomic force microscopy force-spectroscopy experiment. The nanomechanical properties of a one-component supported lipid membrane (SLM) exhibiting areas of two different thicknesses are studied: While a standard contact mechanics model (Sneddon) provides two different elastic moduli for these two morphologies, it is shown that Garcia''s bottom-effect artifact correction yields a unique value, as expected for an intrinsic material property. Remarkably, it is demonstrated that the ratio between the contact radius (and not only the indentation) and the sample thickness is the key parameter addressing the relevance of the bottom-effect artifact. The experimental results are validated by finite element method simulations providing a solid support to Garcia''s theory. The amphiphilic nature of the investigated material is representative of several kinds of lipids, suggesting that the results have far reaching implications for determining the correct Young''s modulus of SLMs. The generality of Garcia''s bottom-effect artifact correction allows its application to every kind of supported soft film

Human platelet lysate stimulates neurotrophic properties of human adipose-derived stem cells better than Schwann cell-like cells

Background: Trauma-associated peripheral nerve injury is a widespread clinical problem causing sensory and motor disabilities. Schwann cells (SCs) contribute to nerve regeneration, mainly by secreting nerve growth factor (NGF) and brain-derived neurotrophic factor. In the last years, adipose-derived stem cells (ASCs) differentiated into SCs (SC-ASCs) were considered as promising cell therapy. However, the cell trans-differentiation process has not been effectively showed and presents several drawbacks, thus an alternative approach for increasing ASCs neurotrophic properties is highly demanded. In the context of human cell-based therapies, Good Manufacturing Practice directions indicate that FBS should be substituted with a xenogeneic-free supplement, such as Human Platelet Lysate (HPL). Previously, we demonstrated that neurotrophic properties of HPL-cultured ASCs were superior compared to undifferentiated FBS-cultured ASCs. Therefore, as following step, here we compared the neurotrophic properties of differentiated SC-like ASCs and HPL-cultured ASCs.Methods: Both cell groups were investigated for gene expression level of neurotrophic factors, their receptors and neuronal markers. Moreover, the expression of nestin was quantitatively evaluated by flow cytometry. The commitment toward the SC phenotype was assessed with immunofluorescence pictures. Proteomics analysis was performed on both cells and their conditioned media to compare the differential protein profile. Finally, neurotrophic abilities of both groups were evaluated with a functional co-culture assay, assessing dorsal root ganglia survival and neurite outgrowth.Results: HPL-cultured ASCs demonstrated higher gene expression of NGF and lower expression of S100B. Moreover, nestin was present in almost all HPL-cultured ASCs and only in one quarter of SC-ASCs. Immunofluorescence confirmed that S100B was not present in HPL-cultured ASCs. Proteomics analysis validated the higher expression of nestin and the increase in cytoskeletal and ECM proteins involved in neural regeneration processes. The co-culture assay highlighted that neurite outgrowth was higher in the presence of HPL-ASCs or their conditioned medium compared to SC-ASCs.Conclusions: All together, our results show that HPL-ASCs were more neurotrophic than SC-ASCs. We highlighted that the HPL triggers an immature neuro-induction state of ASCs, while keeping their stem properties, paving the way for innovative therapies for nerve regeneration. Graphical Abstrac

Estudio e investigaciones realizadas en el LEMIT sobre materiales empleados en edificios históricos

Cuando se abordan problemas de restauración, reparación y conservación de edificios y construcciones de valor histórico se debe realizar, antes de iniciar las tareas de puesta en valor, un estudio integral de las causales que han provocado los deterioros. Esta situación es de primordial importancia, ya que si no se eliminan las causales, rápidamente reaparecen los signos externos de las alteraciones. Sin embargo, muchas de las alteraciones y/o deterioros de las construcciones de valor patrimonial y/o de los materiales que las constituyen se deben, con exclusividad, al pasaje del tiempo (vida en servicio de la construcción). Los materiales empleados en la construcción experimentan procesos de deterioro por reacciones físico, químicas o físico-químicas entre el material y los agentes agresivos o el originado por el crecimiento de microorganismos, en particular algas en sectores húmedos y sombríos y/o líquenes o plantas mayores como por ejemplo helechos. En este trabajo se presentan investigaciones y estudios de distintos materiales constituyentes de construcciones de valor patrimonial, en particular, se analizan ladrillos cerámicos comunes, mezclas de asiento, morteros internos y externos, tejas y materiales de revestimiento (cerámicos, pinturas y papel). Estos estudios fueron realizados para la caracterización de los materiales y/o para disponer de información técnica para su restauración o reemplazo. En todos los casos, se informan las técnicas de caracterización mecánica, física y química empleadas para su evaluación. En algunos casos, se realizan estudios de difracción de rayos X, microscopia electrónica de barrido (SEM), cortes petrográficos, análisis en lupa microscópica y microscopio petrográfico. Además, se han aplicado técnicas para determinar color y rugosidad

Effects of Metal Micro and Nano-Particles on hASCs: An In Vitro Model

As the knowledge about the interferences of nanomaterials on human staminal cells are scarce and contradictory, we undertook a comparative multidisciplinary study based on the size effect of zero-valent iron, cobalt, and nickel microparticles (MPs) and nanoparticles (NPs) using human adipose stem cells (hASCs) as a model, and evaluating cytotoxicity, morphology, cellular uptake, and gene expression. Our results suggested that the medium did not influence the cell sensitivity but, surprisingly, the iron microparticles (FeMPs) resulted in being toxic. These data were supported by modifications in mRNA expression of some genes implicated in the inflammatory response. Microscopic analysis confirmed that NPs, mainly internalized by endocytosis, persist in the vesicles without any apparent cell damage. Conversely, MPs are not internalized, and the effects on hASCs have to be ascribed to the release of ions in the culture medium, or to the reduced oxygen and nutrient exchange efficiency due to the presence of MP agglomerating around the cells. Notwithstanding the results depicting a heterogeneous scene that does not allow drawing a general conclusion, this work reiterates the importance of comparative investigations on MPs, NPs, and corresponding ions, and the need to continue the thorough verification of NP and MP innocuousness to ensure unaffected stem cell physiology and differentiation

Bottom Effect in Atomic Force Microscopy Nanomechanics

In this work, the influence of the rigid substrate on the determination of the sample Young's modulus, the so‐called bottom‐effect artifact, is demonstrated by an atomic force microscopy force‐spectroscopy experiment. The nanomechanical properties of a one‐component supported lipid membrane (SLM) exhibiting areas of two different thicknesses are studied: While a standard contact mechanics model (Sneddon) provides two different elastic moduli for these two morphologies, it is shown that Garcia's bottom‐effect artifact correction yields a unique value, as expected for an intrinsic material property. Remarkably, it is demonstrated that the ratio between the contact radius (and not only the indentation) and the sample thickness is the key parameter addressing the relevance of the bottom‐effect artifact. The experimental results are validated by finite element method simulations providing a solid support to Garcia's theory. The amphiphilic nature of the investigated material is representative of several kinds of lipids, suggesting that the results have far reaching implications for determining the correct Young's modulus of SLMs. The generality of Garcia's bottom‐effect artifact correction allows its application to every kind of supported soft film.S.R.‐R. and P.D.G. contributed equally to this work. S.C., S.M., and P.C. are grateful for financial assistance from the European MagicCellGene Project (M‐ERA.NET COFUND call 2016, Ministerio de Economía y Competitividad from Spain in the framework of project PCIN‐2017‐127). P.C. and S.M. also acknowledge support from DGA and Fondos FEDER for funding Platon research group (E31_17R). K.K. and D.B.W. are grateful to the German Science Foundation (SFB 803, project A05) for financial support.Peer reviewe

Deep phenotype characterization of hypertensive response to exercise: implications on functional capacity and prognosis across the heart failure spectrum

Aims: Limited evidence is available regarding the role of hypertensive response to exercise (HRE) in heart failure (HF). We evaluated the systolic blood pressure (SBP) to workload slope during exercise across the HF spectrum, investigating haemodynamic and prognostic correlates of HRE. Methods and results: We prospectively enrolled 369 patients with HF Stage C (143 had preserved [HFpEF], and 226 reduced [HFrEF] ejection fraction), 201 subjects at risk of developing HF (HF Stages A-B), and 58 healthy controls. We performed a combined cardiopulmonary exercise stress echocardiography testing. We defined HRE as the highest sex-specific SBP/workload slope tertile in each HF stage. Median SBP/workload slope was 0.53 mmHg/W (interquartile range 0.36-0.72); the slope was 39% steeper in women than men (p < 0.0001). After adjusting for age and sex, SBP/workload slope in HFrEF (0.47, 0.30-0.63) was similar to controls (0.43, 0.35-0.57) but significantly lower than Stages A-B (0.61, 0.47-0.75) and HFpEF (0.63, 0.42-0.86). Patients with HRE showed significantly lower peak oxygen consumption and peripheral oxygen extraction. After a median follow-up of 16 months, HRE was independently associated with adverse outcomes (all-cause mortality and hospitalization for cardiovascular reasons: hazard ratio 2.05, 95% confidence interval 1.81-5.18), while rest and peak SBP were not. Kaplan-Meier analysis confirmed a worse survival probability in Stages A-B (p = 0.005) and HFpEF (p < 0.001), but not HFrEF. Conclusion: A steeper SBP/workload slope is associated with impaired functional capacity across the HF spectrum and could be a more sensitive predictor of adverse events than absolute SBP values, mainly in patients in Stages A-B and HFpEF

Ventricular-Arterial Coupling Derived From Proximal Aortic Stiffness and Aerobic Capacity Across the Heart Failure Spectrum

Objectives: This study aimed to evaluate ventricular-arterial coupling (VAC) across the spectrum of heart failure (HF). Background: VAC can be evaluated as the ratio between arterial stiffness (pulsed wave velocity [PWV]) and myocardial deformation (global longitudinal strain [GLS]). Methods: The authors introduced a Doppler-derived, single-beat technique to estimate aortic arch PWV (aa-PWV) in addition to tonometry-derived carotid-femoral PWV (cf-PWV). They measured PWVs and GLS in 155 healthy controls, 75 subjects at risk of developing HF (American College of Cardiology/American Heart Association stage A-B) and 236 patients in stage C heart failure with preserved ejection fraction (HFpEF) (n = 104) or heart failure with reduced ejection fraction (HFrEF) (n = 132). They evaluated peak oxygen consumption and peripheral extraction using combined cardiopulmonary-echocardiography exercise stress. Results: aa-PWV was obtainable in all subjects and significantly lower than cf-PWV in all subgroups (P &lt; 0.01). PWVs were directly related and increased with age (all P &lt; 0.0001). cf-PWV/GLS was similarly compromised in HFrEF (1.09 ± 0.35) and HFpEF (1.05 ± 0.21), whereas aa-PWV/GLS was more impaired in HFpEF (0.70 ± 0.10) than HFrEF (0.61 ± 0.14; P &lt; 0.01). Stage A-B had values of cf-PWV/GLS and aa-PWV/GLS (0.67 ± 0.27 and 0.48 ± 0.14, respectively) higher than controls (0.46 ± 0.11 and 0.39 ± 0.10, respectively) but lower than stage C (all P &lt; 0.01). Peak arteriovenous oxygen difference (AVO2diff) was inversely related with cf-PWV/GLS and aa-PWV/GLS (all P &lt; 0.01). Although cf-PWV/GLS and aa-PWV/GLS independently predicted peak VO2 in the overall population (adjusted R2 = 0.33 and R2= 0.36; all P &lt; 0.0001), only aa-PWV/GLS was independently associated with flow reserve during exercise (R2 = 0.52; P &lt; 0.0001). Conclusions: Abnormal VAC is directly correlated with greater severity of HF and worse functional capacity. HFpEF shows a worse VAC than HFrEF when expressed by aa-PWV/GLS

Ventricular-Arterial Coupling Derived From Proximal Aortic Stiffness and Aerobic Capacity Across the Heart Failure Spectrum

Background: Ventricular-arterial coupling (VAC) can be evaluated as the ratio between arterial stiffness (pulsed wave velocity [PWV]) and myocardial deformation (global longitudinal strain [GLS]). Objectives: This study aimed to evaluate VAC across the spectrum of heart failure (HF). Methods: The authors introduced a Doppler-derived, single-beat technique to estimate aortic arch PWV (aa-PWV) in addition to tonometry-derived carotid-femoral PWV (cf-PWV). They measured PWVs and GLS in 155 healthy controls, 75 subjects at risk of developing HF (American College of Cardiology/American Heart Association stage A-B) and 236 patients in stage C heart failure with preserved ejection fraction (HFpEF) (n = 104) or heart failure with reduced ejection fraction (HFrEF) (n = 132). They evaluated peak oxygen consumption and peripheral extraction using combined cardiopulmonary-echocardiography exercise stress. Results: aa-PWV was obtainable in all subjects and significantly lower than cf-PWV in all subgroups (P < 0.01). PWVs were directly related and increased with age (all P < 0.0001). cf-PWV/GLS was similarly compromised in HFrEF (1.09 ± 0.35) and HFpEF (1.05 ± 0.21), whereas aa-PWV/GLS was more impaired in HFpEF (0.70 ± 0.10) than HFrEF (0.61 ± 0.14; P < 0.01). Stage A-B had values of cf-PWV/GLS and aa-PWV/GLS (0.67 ± 0.27 and 0.48 ± 0.14, respectively) higher than controls (0.46 ± 0.11 and 0.39 ± 0.10, respectively) but lower than stage C (all P < 0.01). Peak arteriovenous oxygen difference (AVO2diff) was inversely related with cf-PWV/GLS and aa-PWV/GLS (all P < 0.01). Although cf-PWV/GLS and aa-PWV/GLS independently predicted peak VO2 in the overall population (adjusted R2 = 0.33 and R2= 0.36; all P < 0.0001), only aa-PWV/GLS was independently associated with flow reserve during exercise (R2 = 0.52; P < 0.0001). Conclusions: Abnormal VAC is directly correlated with greater severity of HF and worse functional capacity. HFpEF shows a worse VAC than HFrEF when expressed by aa-PWV/GLS. Keywords: exercise capacity; heart failure; heart failure with preserved ejection fraction (HFpEF); pulsed wave velocity; ventricular-arterial coupling (VAC)

Cardiometabolic Phenotyping in Heart Failure: Differences between Patients with Reduced vs. Preserved Ejection Fraction

Aims. We explored multiple cardiometabolic patterns, including inflammatory and congestive pathways, in patients with heart failure (HF). Methods and Results. We enrolled 270 HF patients with reduced (n = 96) and preserved (≥50%, HFpEF; n = 174) ejection fraction. In HFpEF, glycated hemoglobin (Hb1Ac) seemed to be relevant in its relationship with inflammation as Hb1Ac positively correlated with high-sensitivity C-reactive protein (hs-CRP; Spearman’s rank correlation coefficient ρ = 0.180, p p p p p p < 0.05). Conclusion. In HF patients, HFpEF and HFrEF phenotypes are characterized by different cardiometabolic indices related to distinct inflammatory and congestive pathways. Patients with HFpEF showed an important relationship between inflammatory and cardiometabolic parameters. Conversely, in HFrEF, there is a significant relationship between congestion and inflammation, while cardiometabolism appears not to influence inflammation, instead affecting sympathetic hyperactivation

Bio-Humoral and Non-Invasive Haemodynamic Correlates of Renal Venous Flow Patterns across the Heart Failure Spectrum

Background: We evaluated the bio-humoral and non-invasive haemodynamic correlates of renal congestion evaluated by Doppler renal venous flow (RVF) across the heart failure (HF) spectrum, from asymptomatic subjects with cardiovascular risk factors (Stage A) and structural heart disease (Stage B) to patients with clinically overt HF (Stage C). Methods: Ultrasound evaluation, including echocardiography, lung ultrasound and RVF, along with blood and urine sampling, was performed in 304 patients. Results: Continuous RVF was observed in 230 patients (76%), while discontinuous RVF (dRVF) was observed in 74 (24%): 39 patients had pulsatile RVF, 18 had biphasic RVF and 17 had monophasic RVF. Stage C HF was significantly more common among patients with dRVF. Monophasic RVF was associated with worse renal function and a higher urinary albumin-to-creatinine ratio (uACR). After adjusting for hypertension, diabetes mellitus, the presence of Stage C HF and serum creatinine levels, worsening RVF patterns were associated with higher NT-proBNP levels, worse right ventricular-arterial coupling, larger inferior vena cava and higher echo-derived pulmonary artery wedge pressure. This trend was confirmed when only patients with HF Stage C were analysed after adjusting for the left ventricle ejection fraction (LVEF). Conclusion: Abnormal RVF is common across the HF spectrum. Worsening RVF patterns are independently associated with increased congestion, worse non-invasive haemodynamics and impaired RV-arterial coupling. RVF evaluation could refine prognostic stratification across the HF spectrum, irrespective of LVEF