p-Aminobenzamidine attenuates cardiovascular dysfunctions in spontaneously hypertensive rats.

AIMS: Diminazene aceturate, a putative ACE2 activator, is susceptible to cleavage resulting in the formation of p-aminobenzamidine (PAB). This study aimed to investigate the effects of PAB in addressing cardiovascular dysfunctions in spontaneously hypertensive rats (SHR). MAIN METHODS: Acute effects of PAB on mean arterial pressure (MAP), heart rate (HR), and aortic (AVC) and mesenteric vascular conductance (MVC) were evaluated in anesthetized SHR. Isolated aortic rings and the Langendorff technique were used to investigate the acute and chronic effects of PAB in the artery and heart. Chronic treatment with PAB (1 mg/kg, gavage) was carried out for 60 days. During this period, systolic blood pressure (SBP) and HR were measured by tail-cuff plethysmography. After the treatment, the left ventricle was collected for histology analyses, western blotting, and ACE2 activity. KEY FINDINGS: Bolus infusion of PAB acutely reduced MAP and increased both AVC and MVC in SHR. Additionally, PAB induced coronary and aorta vasodilation in isolated organs from Wistar and SHR in an endothelial-dependent manner. The chronic PAB treatment in SHR significantly attenuated the increase of SBP and improved the aorta vasorelaxation induced by acetylcholine and bradykinin-induced coronary vasodilation. In addition, chronic treatment with PAB attenuated the cardiomyocyte hypertrophy and extracellular matrix deposition in hearts from SHR. PAB did not alter the protein expression of the AT1, AT2, Mas, ACE, ACE2, or ACE2 activity. SIGNIFICANCE: PAB induced beneficial effects on cardiovascular dysfunctions induced by hypertension, suggesting that this molecule could be used in the development of new drugs for the treatment of cardiovascular diseases.

miR-146a-5p modulates cellular senescence and apoptosis in visceral adipose tissue of long-lived Ames dwarf mice and in cultured pre-adipocytes.

MicroRNAs (miRNAs) are potent regulators of multiple biological processes. Previous studies have demonstrated that miR-146a-5p increases in normal mice during aging, while long-living Ames dwarf (df/df) mice maintain youthful levels of this miRNA. The aim of this study was to elucidate the involvement of miR-146a-5p in modulating cellular senescence and apoptosis in visceral adipose tissue of df/df mice and cultured pre-adipocytes. To test the effects of miR-146a-5p overexpression on visceral adipose tissue, wild-type, and df/df mice, were treated with miRNA-negative control-base and df/df were transfected with 4 or 8 µg/g of a miR-146a-5p mimetic, respectively. Effects of miR-146a-5p overexpression were also evaluated in 3T3-L1 cells cultured under high and normal glucose conditions. Treatment with miR-146a-5p mimetic increased cellular senescence and inflammation and decreased pro-apoptotic factors in visceral adipose tissue of df/df mice. The miR-146a-5p mimetic induced similar effects in 3T3-L1 cells cultivated at normal but not high glucose levels. Importantly, 3T3-L1 HG cells in high glucose conditions showed significantly higher expression of miR-146a-5p than 3T3-L1 grown in normal glucose conditions. These results indicate that miR-146a-5p can be a marker for cellular senescence. This miRNA represents one of the significant SASP factors that if not precisely regulated, can accentuate inflammatory responses and stimulate senescence in surrounding non-senescent cells. The role of miR-146a-5p is different in healthy versus stressed cells, suggesting potential effects of this miRNA depend on overall organismal health, aging, and metabolic state.

Specific PIWI-Interacting RNAs and Related Small Noncoding RNAs Are Associated With Ovarian Aging in Ames Dwarf (df/df) Mice.

The Ames dwarf (df/df) mouse is a well-established model for delayed aging. MicroRNAs (miRNAs), the most studied small noncoding RNAs (sncRNAs), may regulate ovarian aging to maintain a younger ovarian phenotype in df/df mice. In this study, we profile other types of ovarian sncRNAs, PIWI-interacting RNAs (piRNAs) and piRNA-like RNAs (piLRNAs), in young and aged df/df and normal mice. Half of the piRNAs derive from transfer RNA fragments (tRF-piRNAs). Aging and dwarfism alter the ovarian expression of these novel sncRNAs. Specific tRF-piRNAs that increased with age might target and decrease the expression of the breast cancer antiestrogen resistance protein 3 (BCAR3) gene in the ovaries of old df/df mice. A set of piLRNAs that decreased with age and map to D10Wsu102e mRNA may have trans-regulatory functions. Other piLRNAs that decreased with age potentially target and may de-repress transposable elements, leading to a beneficial impact on ovarian aging in df/df mice. These results identify unique responses in ovarian tissues with regard to aging and dwarfism. Overall, our findings highlight the complexity of the aging effects on gene expression and suggest that, in addition to miRNAs, piRNAs, piLRNAs, tRF-piRNAs, and their potential targets can be central players in the maintenance of a younger ovarian phenotype in df/df mice.

Circulating microRNA profile in humans and mice with congenital GH deficiency.

Reduced inflammation, increased insulin sensitivity, and protection against cancer are shared between humans and mice with GH/IGF1 deficiency. Beyond hormone levels, miRNAs are important regulators of metabolic changes associated with healthy aging. We hypothesized that GH deficiency in humans alters the abundance of circulating miRNAs and that a subset of those miRNAs may overlap with those found in GH-deficient mice. In this study, subjects with untreated congenital isolated GH deficiency (IGHD; n = 23) and control subjects matched by age and sex (n = 23) were recruited and serum was collected for miRNA sequencing. Serum miRNAs from young (6 month) and old (22 month) Ames dwarf (df/df) mice with GH deficiency and their WT littermates (n = 5/age/genotype group) were used for comparison. We observed 14 miRNAs regulated with a genotype by age effect and 19 miRNAs regulated with a genotype effect independent of age in serum of IGHD subjects. These regulated miRNAs are known for targeting pathways associated with longevity such as mTOR, insulin signaling, and FoxO. The aging function was overrepresented in IGHD individuals, mediated by hsa-miR-31, hsa-miR-146b, hsa-miR-30e, hsa-miR-100, hsa-miR-181b-2, hsa-miR-195, and hsa-miR-181b-1, which target the FoxO and mTOR pathways. Intriguingly, miR-181b-5p, miR-361-3p, miR-144-3p, and miR-155-5p were commonly regulated in the serum of humans and GH-deficient mice. In vitro assays confirmed target genes for the main up-regulated miRNAs, suggesting miRNAs regulated in IGHD individuals can regulate the expression of age-related genes. These findings indicate that systemic miRNAs regulated in IGHD individuals target pathways involved in aging in both humans and mice.

Dasatinib plus quercetin prevents uterine age-related dysfunction and fibrosis in mice.

The uterine fibrosis contributes to gestational outcomes. Collagen deposition in the uterus is related to uterine aging. Senolytic therapies are an option for reducing health complications related to aging. We investigated effects of aging and the senolytic drug combination of dasatinib plus quercetin (D+Q) on uterine fibrosis. Forty mice, 20 young females (03-months) and 20 old females (18-months), were analyzed. Young (Y) and old (O) animals were divided into groups of 10 mice, with one treatment (T) group (YT and OT) and another control © group (YC and OC). Comparative analysis of Pi3k/Akt1/mTor and p53 gene expression and related microRNAs (miR34a, miR34b, miR34c, miR146a, miR449a, miR21a, miR126a, and miR181b) among groups was performed to test effects of age and treatment on collagen deposition pathways. Aging promoted downregulation of the Pi3k/Akt1/mTor signaling pathway (P = 0.005, P = 0.031, and P = 0.028, respectively) as well as a reduction in expression of miR34c (P = 0.029), miR126a (P = 0.009), and miR181b (P = 0.007). D+Q treatment increased p53 gene expression (P = 0.041) and decreased miR34a (P = 0.016). Our results demonstrate a role for the Pi3k/Akt1/mTor signaling pathway in uterine aging and suggest for the first time a possible anti-fibrotic effect in the uterus of D+Q senolytic therapy.

IR-780-Albumin-Based Nanocarriers Promote Tumor Regression Not Only from Phototherapy but Also by a Nonirradiation Mechanism.

IR-780 iodide is a fluorescent dye with optical properties in the near-infrared region that has applications in tumor detection and photothermal/photodynamic therapy. This multifunctional effect led to the development of theranostic nanoparticles with both IR-780 and chemotherapeutic drugs such as docetaxel, doxorubicin, and lonidamine. In this work, we developed two albumin-based nanoparticles containing near-infrared IR-780 iodide multifunctional dyes, one of them possessing a magnetic core. Molecular docking with AutoDock Vina studies showed that IR-780 binds to bovine serum albumin (BSA) with greater stability at a higher temperature, allowing the protein binding pocket to better fit this dye. The theoretical analysis corroborates the experimental protocols, where an enhancement of IR-780 was found coupled to BSA at 60 °C, even 30 days after preparation, in comparison to 30 °C. In vitro assays monitoring the viability of Ehrlich ascites carcinoma cells revealed the importance of the inorganic magnetic core on the nanocarrier photothermal-cytotoxic effect. Fluorescence molecular tomography measurements of Ehrlich tumor-bearing Swiss mice revealed the biodistribution of the nanocarriers, with marked accumulation in the tumor tissue (≈3% ID). The histopathological analysis demonstrated strong increase in tumoral necrosis areas after 24 and 72 h after treatment, indicating tumor regression. Tumor regression analysis of nonirradiated animals indicate a IR-780 dose-dependent antitumoral effect with survival rates higher than 70% (animals monitored up to 600 days). Furthermore, an in vivo photothermal therapy procedure was performed and tumor regression was also verified. These results show a novel insight for the biomedical application of IR-780-albumin-based nanocarriers, namely cancer therapy, not only by photoinduced therapy but also by a nonirradiation mechanism. Safety studies (acute oral toxicity, cardiovascular evaluation, and histopathological analysis) suggest potential for clinical translation.

Stimulation of the ACE2/Ang-(1-7)/Mas axis in hypertensive pregnant rats attenuates cardiovascular dysfunction in adult male offspring.

The aim of this study was to investigate whether treatment with diminazene aceturate (DIZE), a putative ACE2 activator, or with angiotensin-(1-7) during pregnancy could attenuate the development of cardiovascular dysfunction in the adult offspring of spontaneously hypertensive rats (SHRs). For this, pregnant SHRs received DIZE or Ang-(1-7) throughout gestation. The systolic blood pressure (SBP) was measured in the male offspring from the 6th to16th weeks of age by tail-cuff plethysmography. Thereafter, the left ventricular contractile function and coronary reactivity were evaluated by the Langendorff technique. Samples of the left ventricles (LVs) and kidneys were collected for histology and western blot assay in another batch of adult rat offspring. Maternal treatment with DIZE or Ang-(1-7) during pregnancy attenuated the increase in SBP in adult offspring. In addition, both DIZE and Ang-(1-7) treatments reduced the cardiomyocyte diameter and fibrosis deposition in the LV, and treatment with Ang-(1-7) also reduced the fibrosis deposition in the kidneys. Maternal treatment with DIZE, as well as Ang-(1-7), improved the coronary vasodilation induced by bradykinin in isolated hearts from adult offspring. However, no difference was observed in the contractile function of the LVs of these animals. The expression levels of AT1 and Mas receptors, ACE, ACE2, SOD, and catalase in the LV were not modified by maternal treatment with Ang-(1-7), but this treatment elicited a reduction in AT2 expression. These data show that treatment with DIZE or Ang-(1-7) during gestation promoted beneficial effects of attenuating hypertension and cardiac remodeling in adult offspring.

Albumin Coating Prevents Cardiac Effect of the Magnetic Nanoparticles.

We have showed that surface layer can determine cardiac effects of the magnetic nanoparticles (MNPs). Considering the high binding capacity of albumin and low side-effects, the aim of this study was to evaluate the influence of albumin coating on the cardiovascular effects of two manganese ferrite-based MNPs: citrate-coated and bare MNPs. Isolated rat hearts were perfused with citrate-coated magnetic nanoparticles (CiMNPs), citrate albumin-coated magnetic nanoparticles (CiAlbMNPs), bare magnetic nanoparticles (BaMNPs), and albumin-coated magnetic nanoparticles (AlbMNPs). CiMNPs induce a transient decrease in the left ventricular end-systolic pressure, +dP/dt and -dP/dt. These effects were not worsened by albumin coating. BaMNPs significantly increased the left ventricular end-diastolic pressure and perfusion pressure and decreased the +dP/dt and -dP/dt. These effects were completely absent in hearts perfused with AlbMNPs. None of the MNPs changed heart rate or arterial blood pressure in conscious rats. Magnetic signals in isolated hearts perfused with BaMNPs were significantly higher than AlbMNPs perfused hearts. However, the magnetic signal in heart tissue was similar when the MNPs were infused in conscious rats. These data indicate that albumin-coated can reduce cardiovascular effects of MNPs. These findings suggest a protective effect of albumin surface in MNPs, favoring its future therapeutic applications.

Manganese ferrite-based nanoparticles induce ex vivo, but not in vivo, cardiovascular effects.

Magnetic nanoparticles (MNPs) have been used for various biomedical applications. Importantly, manganese ferrite-based nanoparticles have useful magnetic resonance imaging characteristics and potential for hyperthermia treatment, but their effects in the cardiovascular system are poorly reported. Thus, the objectives of this study were to determine the cardiovascular effects of three different types of manganese ferrite-based magnetic nanoparticles: citrate-coated (CiMNPs); tripolyphosphate-coated (PhMNPs); and bare magnetic nanoparticles (BaMNPs). The samples were characterized by vibrating sample magnetometer, X-ray diffraction, dynamic light scattering, and transmission electron microscopy. The direct effects of the MNPs on cardiac contractility were evaluated in isolated perfused rat hearts. The CiMNPs, but not PhMNPs and BaMNPs, induced a transient decrease in the left ventricular end-systolic pressure. The PhMNPs and BaMNPs, but not CiMNPs, induced an increase in left ventricular end-diastolic pressure, which resulted in a decrease in a left ventricular end developed pressure. Indeed, PhMNPs and BaMNPs also caused a decrease in the maximal rate of left ventricular pressure rise (+dP/dt) and maximal rate of left ventricular pressure decline (-dP/dt). The three MNPs studied induced an increase in the perfusion pressure of isolated hearts. BaMNPs, but not PhMNPs or CiMNPs, induced a slight vasorelaxant effect in the isolated aortic rings. None of the MNPs were able to change heart rate or arterial blood pressure in conscious rats. In summary, although the MNPs were able to induce effects ex vivo, no significant changes were observed in vivo. Thus, given the proper dosages, these MNPs should be considered for possible therapeutic applications.