Objectives: Extracellular vesicles (EVs) are key biological mediators of several physiological functions within the cell microenvironment. Platelets are the most abundant source of EVs in the blood. Similarly, platelet lysate (PL), the best platelet derivative and angiogenic performer for regenerative purposes, is enriched of EVs, but their role is still too poorly discovered to be suitably exploited. Here, we explored the contribution of the EVs in PL, by investigating the angiogenic features extrapolated from that possessed by PL.Methods: We tested angiogenic ability and molecular cargo in 3D bioprinted models and by RNA sequencing analysis of PL‐derived EVs.Results: A subset of small vesicles is highly represented in PL. The EVs do not retain aggregation ability, preserving a low redox state in human umbilical vein endothelial cells (HUVECs) and increasing the angiogenic tubularly‐like structures in 3D endothelial bioprinted constructs. EVs resembled the miRNome profile of PL, mainly enriched with small RNAs and a high amount of miR‐126, the most abundant angiogenic miRNA in platelets. The transfer of miR‐126 by EVs in HUVEC after the in vitro inhibition of the endogenous form, restored angiogenesis, without involving VEGF as a downstream target in this system.Conclusion: PL is a biological source of available EVs with angiogenic effects involving a miRNAs‐based cargo. These properties can be exploited for targeted molecular/biological manipulation of PL, by potentially developing a product exclusively manufactured of EVs.

The potential role of brown and beige adipose tissue against obesity has been recognized. Browning, or beiging of white adipose tissue (WAT) is associated with the remodeling of adipocytes and the improvement of their metabolic and secretory functions. Here, palmitoylethanolamide (PEA) restore the plasticity of brown and white adipocytes impaired in mice on a high-fat diet (HFD). Young male C57Bl/6J mice were fed with control (STD) diet or HFD for 12 weeks. Ultramicronized PEA (30 mg/kg/die p.o.) was administered for an additional 7 weeks, together with HFD. PEA recovered interscapular brown fat morphology and function, increasing UCP1 positivity, noradrenergic innervation, and inducing the mRNA transcription of several specialized thermogenic genes. PEA promotes the beige-conversion of the subcutaneous WAT, increasing thermogenic markers and restoring leptin signaling and tissue hormone sensitivity. The pivotal role of lipid-sensing peroxisome proliferator-activated receptor (PPAR)-α in PEA effects was determined in mature 3T3-L1. Moreover, PEA improved mitochondrial bioenergetics in mature adipocytes measured by a Seahorse analyzer and induced metabolic machinery via AMPK phosphorylation. All these outcomes were dampened by the receptor antagonist GW6471. Finally, PEA induced adipogenic differentiation and increased AMPK phosphorylation in human adipose-derived stromal cells (ASCs) obtained from subcutaneous WAT of normal-weight patients and patients with obesity. We identify PEA and PPAR-α activation as the main mechanism by which PEA can rewire energy-storing white into energy-consuming brown-like adipocytes via multiple and converging effects that restore WAT homeostasis and metabolic flexibility.

Indirect evidence suggests that adipose tissue-derived stromal cells (ASCs) possess different physiological and biological variations related to the anatomical localization of the adipose depots. Accordingly, to investigate the influence of the tissue origin on the intrinsic properties of ASCs and to assess their response to specific stimuli, we compared the biological, functional and ultrastructural properties of two ASC pools derived from mediastinal and subcutaneous depots (thoracic compartment) by means of supplements such as platelet lysate (PL) and FBS. Subcutaneous ASCs exhibited higher proliferative and clonogenic abilities than mediastinal counterpart, as well as increased secreted levels of IL-6 combined with lower amount of VEGF-C. In contrast, mediastinal ASCs displayed enhanced pro-angiogenic and adipogenic differentiation properties, increased cell diameter and early autophagic processes, highlighted by electron microscopy. Our results further support the hypothesis that the origin of adipose tissue significantly defines the biological properties of ASCs, and that a homogeneric function for all ASCs cannot be assumed.

Fibrosis is a fundamental pathological process driving heart failure progression by promoting extracellular matrix deposition and impairing myocardial compliance. In recent years, the sirtuin family of NAD⁺-dependent deacetylases, traditionally linked to aging and metabolism, has emerged as a key regulator of cardiac fibrotic remodeling. This review investigates the roles of sirtuins in mitigating cardiac fibrosis, with emphasis on mechanisms such as mitochondrial preservation and the therapeutic potential of their modulation. Sirtuin signaling attenuates fibrosis by regulating intracellular pathways that control fibroblast activation. In particular, sirtuin-mediated deacetylation modulates pro-fibrotic mediators, including the TGF-β/Smad pathway, thereby reducing collagen synthesis and fibrotic gene expression. However, their effects are isoform- and context-dependent: SIRT1, SIRT3, SIRT6, and SIRT7 generally exert protective roles, whereas SIRT2 and SIRT5 may display neutral or even pro-fibrotic actions depending on the cell type, disease stage, and experimental context. Recognizing this complexity is essential to evaluate their therapeutic relevance. Building on these mechanistic insights, the review explores the preclinical development of sirtuin-targeted therapies. Strategies include NAD⁺ precursors, natural compounds, novel small-molecule activators with enhanced specificity, and agents that indirectly stimulate sirtuins through metabolic modulation. Such approaches highlight the potential of pharmacologically enhancing sirtuin activity to counteract maladaptive cardiac remodeling and improve outcomes in heart failure. By integrating molecular insights with advances in pharmacology, this review synthesizes the most recent mechanistic findings from the past three years with a dedicated focus on the translational challenges and opportunities of pharmacologically targeting sirtuins for anti-fibrotic therapy.

Tenon’s fibroblasts (TFs), widely employed as in vitro model for many ophthalmological studies, are routinely cultured with FBS. Platelet Lysate (PL), a hemoderivate enriched with growth factors and cytokines has been largely tested in several clinical applications and as substitute of FBS in culture. Here, we investigate whether PL can exert biological effects on TF populations similarly to other cell types. Results show that PL significantly enhances cell proliferation and migration vs. FBS, without influencing cell size/granularity. Upregulation of EGF, VEGF, KDR, MMP2-9, FAK mRNA levels also occurs and phosphorylation of AKT but not of ERK1/2 is significantly enhanced. The inhibition of the PI3kinase/AKT pathway with the specific inhibitor wortmannin, decreases PL-induced cell migration but not proliferation. Condition supernatants containing PL show increased bioavailability of Nitric Oxide and reduced levels of 8-Iso-PGF2-alpha, correlating with cell proliferation and migration. Pro-angiogenic/inflammatory soluble factors (GRO, Angiogenin, EGF, I-309, PARC) are exclusively or greater expressed in media containing PL than FBS. GMP-grade PL preparations positively influence in vitro biological effects of TFs representing a suitable and safer alternative to FBS.