Nanoparticle approaches for the renin-angiotensin system

Systemic Arterial Hypertension and Factors Associated with Blood Pressure Dysregulation in Companion Animals

Systemic arterial hypertension (SAH), characterised by a persistent increase in BP beyond the reference values for the species, is a concerning and detrimental clinical condition. The aim of this manuscript is to present the state of the art on SAH in companion animals, including the different types of hypertension, diagnostic and therapeutic approaches, and the factors associated with its occurrence, such as the role of stress. It also discusses the benefits and challenges related to the measurement process. SAH is categorised into types based on the underlying cause: situational, secondary, and idiopathic (the least frequently observed). The situational type occurs when stress is the primary factor, such as during veterinary visits, contact with other animals, or in cases of 'white coat syndrome'. If the stressor is removed, BP values tend to normalise. The most common type of SAH is the secondary form, which is associated with an underlying condition, such as renal, cardiac, endocrine, or neurological diseases, or a combination of these. Diagnosing SAH is a challenging task for many veterinarians due to factors related to handling the animal, managing the equipment, and interpreting the results. Consequently, many professionals either take inaccurate measurements or misinterpret the results, often prescribing antihypertensive medications prematurely or unnecessarily. Despite being a well-standardised and well-documented process, challenges persist. Treatment often involves antihypertensive drugs, either alone or in combination, alongside management of the underlying causes, when present. Therefore, BP values should be obtained correctly, with clinical-therapeutic decisions carefully aligned with the factors that may influence them.

Spinorphin Molecules as Opportunities for Incorporation into Spinorphin@AuNPs Conjugate Systems for Potential Sustained Targeted Delivery to the Brain

Background: This study explores the potential for the synthesis of peptide nanosystems comprising spinorphin molecules (with rhodamine moiety: Rh-S, Rh-S5, and Rh-S6) conjugated with nanoparticles (AuNPs), specifically peptide Rh-S@AuNPs, peptide Rh-S5@AuNPs, and peptide Rh-S6@AuNPs, alongside a comparative analysis of the biological activities of free and conjugated peptides. The examination of the microstructural characteristics of the obtained peptide systems and their physicochemical properties constitutes a key focus of this study. Methods: Zeta (ζ) potential, Fourier transformation infrared (FTIR) spectroscopy, circular dichroism (CD), scanning electron microscopy (SEM-EDS), transmission electron microscopy (TEM), and UV-Vis spectrophotometry were employed to elucidate the structure-activity correlations of the peptide@nano AuNP systems. Results: The zeta potential values for all the Rh-S@AuNPs demonstrate that the samples are electrically stable and resistant to flocculation and coagulation. The absorption of energy quanta from UV-Vis radiation by the novel nanopeptide systems does not substantially influence the distinctive signal of AuNPs, which is situated at around 531 nm. The FTIR measurements indicate the signals associated with the unique functional groups of the peptides, whereas circular dichroism verifies the synthesis of the conjugated nanocomposites of the spinorphin@AuNP type. An analysis of the SEM and TEM data revealed that most AuNPs have a spherical morphology, with an average diameter of around 21.92 ± 6.89 nm. The results of the in vivo studies showed promising findings regarding the anticonvulsant properties of the nanocompounds, especially the Rh-S@AuNP formulation. Conclusions: All the nanocompounds tested demonstrated the ability to reduce generalized tonic-clonic seizures. This suggests that these formulations may effectively target the underlying neuronal hyperexcitability. In addition, the prepared Rh-S@AuNP formulations also showed anticonvulsant activity in the maximal electroshock test performed in mice, which was evident after systemic (intraperitoneal) administration. The study's findings indicate that conjugates can be synthesized via a straightforward process, rendering them potential therapeutic agents with biological activity.

Novel AT2R Antagonists for Treating Chronic Pain

Provided herein are novel AT2R antagonists, pharmaceutical compositions, use of such compounds in treating chronic pain, and processes for preparing such compounds.

Aliskiren-Loaded Nanoparticles Downregulate (Pro)renin Receptor and ACE Gene Expression in the Heart of Spontaneously Hypertensive Rats: Effect on NADPH Oxidase

We aimed to determine effects of aliskiren, a direct renin inhibitor, loaded onto polymeric nanoparticles on the (pro)renin receptor (Atp6ap2), angiotensin II type 1 receptor (Agtr1), and angiotensin-converting enzyme (ACE) gene expression in the heart of spontaneously hypertensive rats (SHR). Twelve-week-old male SHRs were divided into an untreated group and groups treated with powdered aliskiren or aliskiren-loaded nanoparticles (25 mg/kg/day). After three weeks, the accumulation of aliskiren, distribution of polymeric nanoparticles, gene expression of Atp6ap2 and Agtr1 receptors and ACE, and protein expression of NADPH oxidase along with the conjugated diene (CD) concentration were analyzed. The accumulation of aliskiren in the heart was higher in the aliskiren-loaded nanoparticle group than in the powdered group. The fluorescent signals of nanoparticles were visible in cardiomyocytes, vessel walls, and erythrocytes. Aliskiren-loaded nanoparticles decreased the gene expression of Atp6ap2 and ACE, while not affecting Agtr1. Both forms of aliskiren decreased the protein expression of NADPH oxidase, with a more pronounced effect observed in the aliskiren-loaded nanoparticle group. CD concentration was decreased only in the aliskiren-loaded nanoparticle group. We hypothesize that aliskiren-loaded nanoparticle-mediated downregulation of Atp6ap2 and ACE may contribute to a decrease in ROS generation with beneficial effects in the heart. Moreover, polymeric nanoparticles may represent a promising tool for targeted delivery of aliskiren.

The Utilization of Plant-Material-Loaded Vesicular Drug Delivery Systems in the Management of Pulmonary Diseases

Medicinal plants have been utilized to treat a variety of conditions on account of the bioactive properties that they contain. Most bioactive constituents from plants are of limited effectiveness, due to poor solubility, limited permeability, first-pass metabolism, efflux transporters, chemical instability, and food-drug interactions However, when combined with vesicular drug delivery systems (VDDS), herbal medicines can be delivered at a predetermined rate and can exhibit site-specific action. Vesicular drug delivery systems are novel pharmaceutical formulations that make use of vesicles as a means of encapsulating and transporting drugs to various locations within the body; they are a cutting-edge method of medication delivery that combats the drawbacks of conventional drug delivery methods. Drug delivery systems offer promising strategies to overcome the bioavailability limitations of bioactive phytochemicals. By improving their solubility, protecting them from degradation, enabling targeted delivery, and facilitating controlled release, drug delivery systems can enhance the therapeutic efficacy of phytochemicals and unlock their full potential in various health conditions. This review explores and collates the application of plant-based VDDS with the potential to exhibit protective effects against lung function loss in the interest of innovative and effective treatment and management of respiratory illnesses.