The use of pharmacologically active compounds to manage and treat diseases is of utmost relevance in clinical practice. It is well recognized that spatial-temporal control over the delivery of these biomolecules will greatly impact their pharmacokinetic profile and ultimately their therapeutic effect. Nanoparticles (NPs) prepared from different materials have been tested successfully in the clinic for the delivery of several biomolecules including non-coding RNAs (siRNA and miRNA) and mRNAs. Indeed, the recent success of mRNA vaccines is in part due to progress in the delivery systems (NP based) that have been developed for many years. In most cases, the identification of the best formulation was done by testing a small number of novel formulations or by modification of pre-existing ones. Unfortunately, this is a low throughput and time-consuming process that hinders the identification of formulations with the highest potential. Alternatively, high-throughput combinatorial design of NP libraries may allow the rapid identification of formulations with the required release and cell/tissue targeting profile for a given application. Combinatorial approaches offer several advantages over conventional methods since they allow the incorporation of multiple components with varied chemical properties into materials, such as polymers or lipid-like materials, that will subsequently form NPs by self-assembly or chemical conjugation processes. The current review highlights the impact of high-throughput in the development of more efficient drug delivery systems with enhanced targeting and release kinetics. It also describes the current challenges in this research area as well as future directions.

Aging is a risk factor for cardiovascular diseases. Through aging, blood vessels become stiffer, less elastic and, thus, with less ability to contract. The objectives of this chapter are to review (i) recent progresses in the characterization of physiological and pathological vascular aging and (ii) in vitro platforms to study vascular aging. Initially, we will discuss the causes and biomarkers of vascular aging. Then we will discuss the main characteristics related to physiological and pathological aging including (i) altered ECM remodeling (e.g. composition, mechanical properties, degradation, calcification of the ECM during aging), (ii) enhanced fibrosis (e.g. causes and mechanisms), (iii) vascular cell dysfunction triggered by chronic oxidative stress, inflammation or senescence, and (iv) altered responses of vascular cells to flow shear stress. Finally, we will discuss in vitro systems to study vascular aging, particularly the effect of biomechanics in aged cells as well as the effect of drugs during vascular aging.

Aging and chronic inflammation are associated with the development of heart failure with preserved ejection fraction (HFpEF). However, cellular senescence as a potential mechanistic link between both events and its pathophysiological and therapeutic role were yet unexplored. Here we show that ZSF1-obese rats, a model of cardiometabolic HFpEF, have exacerbated systemic inflammation and endothelial damage compared to ZSF1-lean littermates. In addition, ZSF1-obese rats accumulated immune and endothelial senescent cells in the peripheral blood and myocardium. Accordingly, the frequency of circulating senescent leukocytes associated with markers of disease severity in HFpEF patients. Notably, systemic treatment of ZSF1-obese rats with Navitoclax, a BCL-2 family inhibitor, reduced senescent cell burden, decreased circulating B-type natriuretic peptide levels, and attenuated inflammation, vascular remodeling and cardiac fibrosis. Our findings advance cellular senescence as a key mechanistic pathway leading to HFpEF and provide proof-of-concept evidence that senolytics are a promising treatment for this disease.

Funding Acknowledgements Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Fundação Ciência e Tecnlogia HFpEF is the most common form of heart disease in the elderly and is associated with high morbidity and mortality. Our understanding of HFpEF pathophysiology is limited and development of efficient therapies that alter the clinical course of the disease has proved greatly challenging. Although aging is a risk factor of HFpEF1, the involvement of aging hallmarks such as cell senescent and immunosenescence is unclear. Recently, a link between endothelial senescence and HFpEF development was demonstrated in mice with accelerated aging [1], endorsing anti-aging pharmacologic as potential new therapeutic alternatives for HFpEF. In fact, the senolytic (drugs that selectively promote apoptosis of senescent cells) ABT-263 has already proven efficacy in the context of cardiovascular diseases. Further studies are needed to clarify the relevance of aging and of anti-aging therapies in the context of HFpEF. Using ZSF1 obese rats (ZSF1-Ob) as model of HFpEF we showed from 18 weeks signs of immunosenescence compared to ZSF1-Ln, namely an increased frequency of circulating myeloid cells and decreased frequency of T and B cells. Concomitantly, expression of pro-inflammatory factors (IL-6, IL-1, TGF-β, TNF-α) was upregulated in peripheral blood mononuclear cells (PBMCs) of ZSF1-Ob which also displayed characteristic features of cell senescence (p21 expression, lysosomal endogenous Beta-galactosidase (SA-B-Gal) senescence-associated secretory phenotype (SASP) and up-regulation of BCL-XL. Importantly, no signs of cellular senescence (SA-B-gal, pH2AX and senescence associated pathways) were found in the main hematopoietic organs (spleen and bone marrow). Alongside, these systemic alterations, an upsurge of cellular senescence was observed in myocardium of ZSF1-Ob rats, particularly in endothelial and hematopoietic cells. Serum of ZSF1-Ob rat was able to induce activation and cellular senescence of cardiac microvascular endothelial cells, indicating that systemic circulating factors may be the upstream mechanism of cellular senescence and dysfunction in HFpEF. Analysis of HFpEF patients and a control cohort adjusted to main co-morbidities further demonstrated accumulation of senescent monocytes in HFpEF patients. In these patients, the senescence marker SA-B-Gal correlated with plasmatic brain natriuretic peptide (BNP) levels and pulmonary artery systolic pressure. Targeting aging hallmarks through the treatment of ZSF1-Ob rat with ABT-263 resulted in a reduction in circulating senescent cells, decreased systemic and local inflammation, re-established immune proportions, restore the levels of circulating BNP and attenuated myocardial remodeling, particularly endothelial dysfunction and fibrosis. Collectively these findings support that premature cellular senescence contributes to the establishment of a deleterious pro-inflammatory environment in HFpEF and that senolytic agents hold promise for the treatment of this syndrome.