Improvement of Osteogenic Differentiation of Mouse Pre-Osteoblastic MC3T3-E1 Cells on Core-Shell Polylactic Acid/Chitosan Electrospun Scaffolds for Bone Defect Repair.

Electrospun hybrid scaffolds composed of synthetic and natural polymers have gained increasing interest in tissue engineering applications over the last decade. In this work, scaffolds composed of polylactic acid electrospun fibers, either treated (P-PLA) or non-treated (PLA) with air-plasma, were coated with high molecular weight chitosan to create a core-shell microfibrous structure. The effective thickness control of the chitosan layer was confirmed by gravimetric, spectroscopic (FTIR-ATR) and morphological (SEM) investigations. The chitosan coating increased the fiber diameter of the microfibrous scaffolds while the tensile mechanical tests, conducted in dry and wet environments, showed a reinforcing action of the coating layer on the scaffolds, in particular when deposited on P-PLA samples. The stability of the Chi coating on both PLA and P-PLA substrates was confirmed by gravimetric analysis, while their mineralization capacity was evaluated though scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS) after immersing the scaffolds in simulated body fluids (SBF) at 37 °C for 1 week. Sample biocompatibility was investigated through cell viability assay and SEM analysis on mouse pre-osteoblastic MC3T3-E1 cells grown on scaffolds at different times (1, 7, 14 and 21 days). Finally, Alizarin Red assay and qPCR analysis suggested that the combination of plasma treatment and chitosan coating on PLA electrospun scaffolds influences the osteoblastic differentiation of MC3T3-E1 cells, thus demonstrating the great potential of P-PLA/chitosan hybrid scaffolds for bone tissue engineering applications.

Effects of Cerebrospinal Fluids from Alzheimer and Non-Alzheimer Patients on Neurons-Astrocytes-Microglia Co-Culture.

Alzheimer's disease (AD) is the most common form of dementia, characterized by the accumulation of ß-amyloid plaques, tau tangles, neuroinflammation, and synaptic/neuronal loss, the latter being the strongest correlating factor with memory and cognitive impairment. Through an in vitro study on a neurons-astrocytes-microglia (NAM) co-culture system, we analyzed the effects of cerebrospinal fluid (CSF) samples from AD and non-AD patients (other neurodegenerative pathologies). Treatment with CSF from AD patients showed a loss of neurofilaments and spheroids, suggesting the presence of elements including CX3CL1 (soluble form), destabilizing the neurofilaments, cellular adhesion processes, and intercellular contacts. The NAM co-cultures were analyzed in immunofluorescence assays for several markers related to AD, such as through zymography, where the expression of proteolytic enzymes was quantified both in cell extracts and the co-cultures' conditioned medium (CM). Through qRT-PCR assays, several genes involved in the formation of ß-amyloid plaque, in phosphorylation of tau, and in inflammation pathways and MMP expression were investigated.

The Cytokine CX3CL1 and ADAMs/MMPs in Concerted Cross-Talk Influencing Neurodegenerative Diseases.

Neuroinflammation plays a fundamental role in the development and progression of neurodegenerative diseases. It could therefore be said that neuroinflammation in neurodegenerative pathologies is not a consequence but a cause of them and could represent a therapeutic target of neuronal degeneration. CX3CL1 and several proteases (ADAMs/MMPs) are strongly involved in the inflammatory pathways of these neurodegenerative pathologies with multiple effects. On the one hand, ADAMs have neuroprotective and anti-apoptotic effects; on the other hand, they target cytokines and chemokines, thus causing inflammatory processes and, consequently, neurodegeneration. CX3CL1 itself is a cytokine substrate for the ADAM, ADAM17, which cleaves and releases it in a soluble isoform (sCX3CL1). CX3CL1, as an adhesion molecule, on the one hand, plays an inhibiting role in the pro-inflammatory response in the central nervous system (CNS) and shows neuroprotective effects by binding its membrane receptor (CX3CR1) present into microglia cells and maintaining them in a quiescent state; on the other hand, the sCX3CL1 isoform seems to promote neurodegeneration. In this review, the dual roles of CX3CL1 and ADAMs/MMPs in different neurodegenerative diseases, such as Alzheimer's disease (AD), Parkinson's disease (PD), Huntington's disease (MH), and multiple sclerosis (MS), are investigated.

CX3CL1 Pathway as a Molecular Target for Treatment Strategies in Alzheimer's Disease.

Alzheimer's disease (AD) is a scourge for patients, caregivers and healthcare professionals due to the progressive character of the disease and the lack of effective treatments. AD is considered a proteinopathy, which means that aetiological and clinical features of AD have been linked to the deposition of amyloid ß (Aß) and hyperphosphorylated tau protein aggregates throughout the brain, with Aß and hyperphosphorylated tau representing classical AD hallmarks. However, some other putative mechanisms underlying the pathogenesis of the disease have been proposed, including inflammation in the brain, microglia activation, impaired hippocampus neurogenesis and alterations in the production and release of neurotrophic factors. Among all, microglia activation and chronic inflammation in the brain gained some attention, with researchers worldwide wondering whether it is possible to prevent and stop, respectively, the onset and progression of the disease by modulating microglia phenotypes. The following key points have been established so far: (i) Aß deposition in brain parenchyma represents repeated stimulus determining chronic activation of microglia; (ii) chronic activation and priming of microglia make these cells lose neuroprotective functions and favour damage and loss of neurons; (iii) quiescent status of microglia at baseline prevents chronic activation and priming, meaning that the more microglia are quiescent, the less they become neurotoxic. Many molecules are known to modulate the quiescent baseline state of microglia, attracting huge interest among scientists as to whether these molecules could be used as valuable targets in AD treatment. The downside of the coin came early with the observation that quiescent microglia do not display phagocytic ability, being unable to clear Aß deposits since phagocytosis is crucial for Aß clearance efficacy. A possible solution for this issue could be found in the modulation of microglia status at baseline, which could help maintain both neuroprotective features and phagocytic ability at the same time. Among the molecules known to influence the baseline status of microglia, C-X3-chemokine Ligand 1 (CX3CL1), also known as Fractalkine (FKN), is one of the most investigated. FKN and its microglial receptor CX3CR1 are crucial players in the interplay between neurons and microglia, modulating the operation of some neural circuits and the efficacy and persistence of immune response against injury. In addition, CX3CL1 regulates synaptic pruning and plasticity in the developmental age and in adulthood, when it strongly impacts the hippocampus neurogenesis of the adult. CX3CL1 has an effect on Aß clearance and tau phosphorylation, as well as in microglia activation and priming. For all the above, CX3CL1/CX3CR1 signalling has been widely studied in relation to AD pathogenesis, and its biochemical pathway could hide molecular targets for novel treatment strategies in AD. This review summarizes the possible role of CX3CL1 in AD pathogenesis and its use as a potential target for AD treatment.

Cerebrospinal and Blood Biomarkers in Alzheimer's Disease: Did Mild Cognitive Impairment Definition Affect Their Clinical Usefulness?

Despite Alzheimer's Disease (AD) being known from the times of Alois Alzheimer, who lived more than one century ago, many aspects of the disease are still obscure, including the pathogenesis, the clinical spectrum definition, and the therapeutic approach. Well-established biomarkers for AD come from the histopathological hallmarks of the disease, which are Aß and phosphorylated Tau protein aggregates. Consistently, cerebrospinal fluid (CSF) Amyloid ß (Aß) and phosphorylated Tau level measurements are currently used to detect AD presence. However, two central biases affect these biomarkers. Firstly, incomplete knowledge of the pathogenesis of diseases legitimates the search for novel molecules that, reasonably, could be expressed by neurons and microglia and could be detected in blood simpler and earlier than the classical markers and in a higher amount. Further, studies have been performed to evaluate whether CSF biomarkers can predict AD onset in Mild Cognitive Impairment (MCI) patients. However, the MCI definition has changed over time. Hence, the studies on MCI patients seem to be biased at the beginning due to the imprecise enrollment and heterogeneous composition of the miscellaneous MCI subgroup. Plasma biomarkers and novel candidate molecules, such as microglia biomarkers, have been tentatively investigated and could represent valuable targets for diagnosing and monitoring AD. Also, novel AD markers are urgently needed to identify molecular targets for treatment strategies. This review article summarizes the main CSF and blood AD biomarkers, underpins their advantages and flaws, and mentions novel molecules that can be used as potential biomarkers for AD.

Mimicking Molecular Pathways in the Design of Smart Hydrogels for the Design of Vascularized Engineered Tissues.

Biomaterials are pivotal in supporting and guiding vascularization for therapeutic applications. To design effective, bioactive biomaterials, understanding the cellular and molecular processes involved in angiogenesis and vasculogenesis is crucial. Biomaterial platforms can replicate the interactions between cells, the ECM, and the signaling molecules that trigger blood vessel formation. Hydrogels, with their soft and hydrated properties resembling natural tissues, are widely utilized; particularly synthetic hydrogels, known for their bio-inertness and precise control over cell-material interactions, are utilized. Naturally derived and synthetic hydrogel bases are tailored with specific mechanical properties, controlled for biodegradation, and enhanced for cell adhesion, appropriate biochemical signaling, and architectural features that facilitate the assembly and tubulogenesis of vascular cells. This comprehensive review showcases the latest advancements in hydrogel materials and innovative design modifications aimed at effectively guiding and supporting vascularization processes. Furthermore, by leveraging this knowledge, researchers can advance biomaterial design, which will enable precise support and guidance of vascularization processes and ultimately enhance tissue functionality and therapeutic outcomes.

Microglial Activation and Priming in Alzheimer's Disease: State of the Art and Future Perspectives.

Alzheimer's Disease (AD) is the most common cause of dementia, having a remarkable social and healthcare burden worldwide. Amyloid ß (Aß) and protein Tau aggregates are disease hallmarks and key players in AD pathogenesis. However, it has been hypothesized that microglia can contribute to AD pathophysiology, as well. Microglia are CNS-resident immune cells belonging to the myeloid lineage of the innate arm of immunity. Under physiological conditions, microglia are in constant motion in order to carry on their housekeeping function, and they maintain an anti-inflammatory, quiescent state, with low expression of cytokines and no phagocytic activity. Upon various stimuli (debris, ATP, misfolded proteins, aggregates and pathogens), microglia acquire a phagocytic function and overexpress cytokine gene modules. This process is generally regarded as microglia activation and implies that the production of pro-inflammatory cytokines is counterbalanced by the synthesis and the release of anti-inflammatory molecules. This mechanism avoids excessive inflammatory response and inappropriate microglial activation, which causes tissue damage and brain homeostasis impairment. Once the pathogenic stimulus has been cleared, activated microglia return to the naïve, anti-inflammatory state. Upon repeated stimuli (as in the case of Aß deposition in the early stage of AD), activated microglia shift toward a less protective, neurotoxic phenotype, known as "primed" microglia. The main characteristic of primed microglia is their lower capability to turn back toward the naïve, anti-inflammatory state, which makes these cells prone to chronic activation and favours chronic inflammation in the brain. Primed microglia have impaired defence capacity against injury and detrimental effects on the brain microenvironment. Additionally, priming has been associated with AD onset and progression and can represent a promising target for AD treatment strategies. Many factors (genetics, environmental factors, baseline inflammatory status of microglia, ageing) generate an aberrantly activated phenotype that undergoes priming easier and earlier than normally activated microglia do. Novel, promising targets for therapeutic strategies for AD have been sought in the field of microglia activation and, importantly, among those factors influencing the baseline status of these cells. The CX3CL1 pathway could be a valuable target treatment approach in AD, although preliminary findings from the studies in this field are controversial. The current review aims to summarize state of the art on the role of microglia dysfunction in AD pathogenesis and proposes biochemical pathways with possible targets for AD treatment.

Recovery of Bioactive Compounds from Marine Organisms: Focus on the Future Perspectives for Pharmacological, Biomedical and Regenerative Medicine Applications of Marine Collagen.

Marine environments cover more than 70% of the Earth's surface and are among the richest and most complex ecosystems. In terms of biodiversity, the ocean represents an important source, still not widely exploited, of bioactive products derived from species of bacteria, plants, and animals. However, global warming, in combination with multiple anthropogenic practices, represents a serious environmental problem that has led to an increase in gelatinous zooplankton, a phenomenon referred to as jellyfish bloom. In recent years, the idea of "sustainable development" has emerged as one of the essential elements of green-economy initiatives; therefore, the marine environment has been re-evaluated and considered an important biological resource. Several bioactive compounds of marine origin are being studied, and among these, marine collagen represents one of the most attractive bio-resources, given its use in various disciplines, such as clinical applications, cosmetics, the food sector, and many other industrial applications. This review aims to provide a current overview of marine collagen applications in the pharmacological and biomedical fields, regenerative medicine, and cell therapy.

Production of Injectable Marine Collagen-Based Hydrogel for the Maintenance of Differentiated Chondrocytes in Tissue Engineering Applications.

Cartilage is an avascular tissue with limited ability of self-repair. The use of autologous chondrocyte transplants represent an effective strategy for cell regeneration; however, preserving the differentiated state, which ensures the ability to regenerate damaged cartilage, represents the main challenge during in vitro culturing. For this purpose, we produced an injectable marine collagen-based hydrogel, by mixing native collagen from the jellyfish Rhizostoma pulmo with hydroxy-phenyl-propionic acid (HPA)-functionalized marine gelatin. This biocompatible hydrogel formulation, due to the ability of enzymatically reticulate using horseradish peroxidase (HPR) and H2O2, gives the possibility of trap cells inside, in the absence of cytotoxic effects, during the cross-linking process. Moreover, it enables the modulation of the hydrogel stiffness merely varying the concentration of H2O2 without changes in the concentration of polymer precursors. The maintenance of differentiated chondrocytes in culture was then evaluated via morphological analysis of cell phenotype, GAG production and cytoskeleton organization. Additionally, gene expression profiling of differentiation/dedifferentiation markers provided evidence for the promotion of the chondrogenic gene expression program. This, combined with the biochemical properties of marine collagen, represents a promising strategy for maintaining in vitro the cellular phenotype in the aim of the use of autologous chondrocytes in regenerative medicine practices.

E-beam crosslinked nanogels conjugated with monoclonal antibodies in targeting strategies.

Poly(N-vinyl pyrrolidone)-based-nanogels (NGs), produced by e-beam irradiation, are conjugated with monoclonal antibodies (mAb) for active targeting purposes. The uptake of immuno-functionalized nanogels is tested in an endothelial cell line, ECV304, using confocal and epifluorescence microscopy. Intracellular localization studies reveal a faster uptake of the immuno-nanogel conjugate with respect to the 'bare' nanogel. The specific internalization pathway of these immuno-nanogels is clarified by selective endocytosis inhibition experiments, flow cytometry and confocal microscopy. Active targeting ability is also verified by conjugating a monoclonal antibody which recognizes the αvß3 integrin on activated endothelial cells. Epifluorescence images of the 'wound healing assay' on ECV304 cells provide evidence of nanogels localization only in the target cells. Therefore, the immuno-nanogels produced have the potential to recognize specific cell types in heterogeneous systems, which makes them promising candidates for targeted drug delivery applications.

MDA-MB-231 and 8701BC breast cancer lines promote the migration and invasiveness of ECV304 cells on 2D and 3D type-I collagen matrix.

Tumor angiogenesis is a multiphasic process, having the extracellular matrix remodeling as critical step. Different classes of proteolytic enzymes in matrix digestion/remodeling are involved. The role of lytic enzymes and their activation mode have not been completely elucidated. Herein, the crosstalk between endothelia and tumor cells, by realization of bi- and three-dimensional endothelial and breast cancer cells co-cultures, were studied in vitro. Particularly, the effects of two tumor conditioned media (TCM) were assessed about endothelial proliferation, migration, and invasiveness. An increase in expression of pro-MMP9 was detected when endothelial cells were cultured in the presence of both TCM; such as an up-regulation of MMP1 and MMP14 and a down-regulation of MMP7. Moreover the increased MMP2 gene expression from one of them and the stimulation MMP3 synthesis from the other one were observed; an increases of ß3-integrin, VEGFA, and DPP4 molecules were detected when endothelia cells are cultured with both TCM. The selection/characterization of elements present in conditioned media from breast cancer cells differently affect endothelial cells, make them potential effectors useful in breast cancer treatment.

Multi-Functional Nanogels for Tumor Targeting and Redox-Sensitive Drug and siRNA Delivery.

(1) Background: A new family of nanosystems able to discern between normal and tumor cells and to release a therapeutic agent in controlled way were synthetized by e-beam irradiation. This technique permits to obtain biocompatible, sterile, carboxyl-functionalized polyvinylpyrrolidone (PVP-co-acrylic acid) nanogels (NGs); (2) Methods: Here, we performed a targeting strategy based on the recognition of over-expressed proteins on tumor cells, like the folate receptor. The selective targeting was demonstrated by co-culture studies and flow cytometry analysis, using folate conjugated NGs. Moreover, nanoparticles were conjugated to a chemotherapeutic drug or to a pro-apoptotic siRNA through a glutathione sensitive spacer, in order to obtain a controlled release mechanism, specific for cancer cells. The drug efficiency was tested on tumor and healthy cells by flow cytometric analysis, confocal and epifluorescence microscopy and cytotoxicity assay; the siRNA effect was investigated by RNAi experiment; (3) Results: The data obtained showed that the use of NGs permits a faster cargo release in cancer cells, in response to high cytosolic glutathione level, also improving their efficacy; (4) Conclusion: The possibility of releasing biological molecules in a controlled way and to recognize a specific tumor target allows overcoming the typical limits of the classic cancer therapy.

Collagen-Based Scaffolds for Chronic Skin Wound Treatment.

Chronic wounds, commonly known as ulcers, represent a significant challenge to public health, impacting millions of individuals every year and imposing a significant financial burden on the global health system. Chronic wounds result from the interruption of the natural wound-healing process due to internal and/or external factors, resulting in slow or nonexistent recovery. Conventional medical approaches are often inadequate to deal with chronic wounds, necessitating the exploration of new methods to facilitate rapid and effective healing. In recent years, regenerative medicine and tissue engineering have emerged as promising avenues to encourage tissue regeneration. These approaches aim to achieve anatomical and functional restoration of the affected area through polymeric components, such as scaffolds or hydrogels. This review explores collagen-based biomaterials as potential therapeutic interventions for skin chronic wounds, specifically focusing on infective and diabetic ulcers. Hence, the different approaches described are classified on an action-mechanism basis. Understanding the issues preventing chronic wound healing and identifying effective therapeutic alternatives could indicate the best way to optimize therapeutic units and to promote more direct and efficient healing.

Dexamethasone dipropionate loaded nanoparticles of α-elastin-g-PLGA for potential treatment of restenosis.

A graft copolymer of α-elastin with poly(lactic-co-glycolic) acid (PLGA) has been synthesized and successfully employed to produce nanoparticles. Exploiting the known biological activity of α-elastin to promote the maintenance of smooth muscle cells (SMCs) contractile phenotype and the antiproliferative effect of glucocorticoids, the aim of this research was to produce drug-loaded nanoparticles suitable for potential treatment of restenosis. In particular, nanoparticles of α-elastin-g-PLGA with a mean size of 200 nm have been produced and loaded with dexamethasone dipropionate (10% w/w), chosen as a model drug that inhibits proliferation of vascular SMCs. These nanoparticles are able to prolong the drug release and show a pronounced sensibility to elastase. Drug unloaded nanoparticles stimulate the differentiation of human umbilical artery smooth muscle cells (HUASMCs) toward the contractile phenotype as demonstrated by immunofluorescence, flow cytofluorimetric, and western blotting analyses. Finally, drug-loaded nanoparticles efficiently reduce viability of HUASMCs as evidenced by 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2- (4-sulfophenyl)-2H-tetrazolium, inner salt (MTS) assay.

Nanoformulations based on collagenases loaded into halloysite/Veegum® clay minerals for potential pharmaceutical applications.

The design and development of nanomaterials capable of penetrate cancer cells is fundamental when anticancer therapy is involved. The use of collagenase (Col) is useful since this enzyme can degrade collagen, mainly present in the tumor extracellular matrix. However, its use is often limited since collagenase suffers from inactivation and short half-life. Use of recombinant ultrapure collagenase or carrier systems for their delivery are among the strategies adopted to increase the enzyme stability. Herein, based on the more stability showed by recombinant enzymes and the possibility to use them in anticancer therapy, we propose a novel strategy to further increase their stability by using halloysite nanotubes (HNTs) as carrier. ColG and ColH were supramolecularly loaded onto HNTs and used as fillers for Veegum gels. The systems could be used for potential local administration of collagenases for solid tumor treatment. All techniques adopted for characterization showed that halloysite interacts with collagenases in different ways depending with the Col considered. Furthermore, the hydrogels showed a very slow release of the collagenases within 24 h. Finally, biological assays were performed by studying the digestion of a type-I collagen matrix highlighting that once released the Col still possessed some activity. Thus we developed carrier systems that could further increase the high recombinant collagenases stability, preventing their inactivation in future in vivo applications for potential local tumor treatment.

Monitoring the macrophage response towards biomaterial implants using label-free imaging.

Understanding the immune system's foreign body response (FBR) is essential when developing and validating a biomaterial. Macrophage activation and proliferation are critical events in FBR that can determine the material's biocompatibility and fate in vivo. In this study, two different macro-encapsulation pouches intended for pancreatic islet transplantation were implanted into streptozotocin-induced diabetes rat models for 15 days. Post-explantation, the fibrotic capsules were analyzed by standard immunohistochemistry as well as non-invasive Raman microspectroscopy to determine the degree of FBR induced by both materials. The potential of Raman microspectroscopy to discern different processes of FBR was investigated and it was shown that Raman microspectroscopy is capable of targeting ECM components of the fibrotic capsule as well as pro and anti-inflammatory macrophage activation states, in a molecular-sensitive and marker-independent manner. In combination with multivariate analysis, spectral shifts reflecting conformational differences in Col I were identified and allowed to discriminate fibrotic and native interstitial connective tissue fibers. Moreover, spectral signatures retrieved from nuclei demonstrated changes in methylation states of nucleic acids in M1 and M2 phenotypes, relevant as indicator for fibrosis progression. This study could successfully implement Raman microspectroscopy as complementary tool to study in vivo immune-compatibility providing insightful information of FBR of biomaterials and medical devices, post-implantation.

Minimalism in radiation synthesis of biomedical functional nanogels.

A scalable, single-step, synthetic approach for the manufacture of biocompatible, functionalized micro- and nanogels is presented. In particular, poly(N-vinyl pyrrolidone)-grafted-(aminopropyl)methacrylamide microgels and nanogels were generated through e-beam irradiation of PVP aqueous solutions in the presence of a primary amino-group-carrying monomer. Particles with different hydrodynamic diameters and surface charge densities were obtained at the variance of the irradiation conditions. Chemical structure was investigated by different spectroscopic techniques. Fluorescent variants were generated through fluorescein isothiocyanate attachment to the primary amino groups grafted to PVP, to both quantify the available functional groups for bioconjugation and follow nanogels localization in cell cultures. Finally, a model protein, bovine serum albumin, was conjugated to the nanogels to demonstrate the attachment of biologically relevant molecules for targeting purposes in drug delivery. The described approach provides a novel strategy to fabricate biohybrid nanogels with a very promising potential in nanomedicine.

3D polylactide-based scaffolds for studying human hepatocarcinoma processes in vitro.

We evaluated the combination of leaching techniques and melt blending of polymers and particles for the preparation of highly interconnected three-dimensional polymeric porous scaffolds for in vitro studies of human hepatocarcinoma processes. More specifically, sodium chloride and poly(ethylene glycol) (PEG) were used as water-soluble porogens to form porous and solvent-free poly(L,D-lactide) (PLA)-based scaffolds. Several characterization techniques, including porosimetry, image analysis and thermogravimetry, were combined to improve the reliability of measurements and mapping of the size, distribution and microarchitecture of pores. We also investigated the effect of processing, in PLA-based blends, on the simultaneous bulk/surface modifications and pore architectures in the scaffolds, and assessed the effects on human hepatocarcinoma viability and cell adhesion. The influence of PEG molecular weight on the scaffold morphology and cell viability and adhesion were also investigated. Morphological studies indicated that it was possible to obtain scaffolds with well-interconnected pores of assorted sizes. The analysis confirmed that SK-Hep1 cells adhered well to the polymeric support and emitted surface protrusions necessary to grow and differentiate three-dimensional systems. PEGs with higher molecular weight showed the best results in terms of cell adhesion and viability.

High Cerebrospinal Fluid CX3CL1 Levels in Alzheimer's Disease Patients but Not in Non-Alzheimer's Disease Dementia.

Alzheimer's disease (AD) is the most common form of cognitive decline worldwide, occurring in about 10% of people older than 65 years. The well-known hallmarks of AD are extracellular aggregates of amyloid ß (Aß) and intracellular neurofibrillary tangles (NFTs) of tau protein. The evidence that Aß overproduction leads to AD has paved the way for the AD pathogenesis amyloid cascade hypothesis, which proposes that the neuronal damage is sustained by Aß overproduction. Consistently, AD cerebrospinal fluid (CSF) biomarkers used in clinical practice, including Aß 1-42, Aß 1-40, Aß 42/40 ratio, and pTau, are related to the amyloid hypothesis. Recently, it was suggested that the Aß deposition cascade cannot fully disclose AD pathogenesis, with other putative players being involved in the pathophysiology of the disease. Among all, one of the most studied factors is inflammation in the brain. Hence, biomarkers of inflammation and microglia activation have also been proposed to identify AD. Among them, CX3 chemokine ligand 1 (CX3CL1) has taken center stage. This transmembrane protein, also known as fractalkine (FKN), is normally expressed in neurons, featuring an N-terminal chemokine domain and an extended mucin-like stalk, following a short intra-cytoplasmatic domain. The molecule exists in both membrane-bound and soluble forms. It is accepted that the soluble and membrane-bound forms of FKN evoke differential signaling within the CNS. Given the link between CX3XL1 and microglial activation, it has been suggested that CX3CL1 signaling disruption could play a part in the pathogenesis of AD. Furthermore, a role for chemokine as a biomarker has been proposed. However, the findings collected are controversial. The current study aimed to describe the cerebrospinal fluid (CSF) levels of CX3XL1 and classical biomarkers in AD patients.

Continuous Microfiber Wire Mandrel-Less Biofabrication for Soft Tissue Engineering Applications.

Suture materials are the most common bioimplants in surgical and clinical practice, playing a crucial role in wound healing and tendon and ligament repair. Despite the assortment available on the market, sutures are still affected by significant disadvantages, including failure in mimicking the mechanical properties of the tissue, excessive fibrosis, and inflammation. This study introduces a mandrel-less electrodeposition apparatus to fabricate continuous microfiber wires of indefinite length. The mandrel-less biofabrication produces wires, potentially used as medical fibers, with different microfiber bundles, that imitate the hierarchical organization of native tissues, and tailored mechanical properties. Microfiber wire morphology and mechanical properties are characterized by scanning electron microscopy, digital image processing, and uniaxial tensile test. Wires are tested in vitro on monocyte/macrophage stimulation and in vivo on a rat surgical wound model. The wires produced by mandrel-less deposition show an increased M2 macrophage phenotype in vitro. The in vivo assessment demonstrates that microfiber wires, compared to the medical fibers currently used, reduce pro-inflammatory macrophage response and preserve their mechanical properties after 30 days of use. These results make this microfiber wire an ideal candidate as a suture material for soft tissue surgery, suggesting a crucial role of microarchitecture in more favorable host response.