Search Results (1,003)

Background/Objectives: Diuretic resistance is a recognized complication in patients with heart failure (HF) and is associated with worse clinical outcomes; however, information regarding its frequency and associated factors in hospitalized patients in Mexico is limited. This study aimed to describe the frequency of diuretic resistance in patients hospitalized with HF in a hospital unit in western Mexico and to identify factors associated with diuretic resistance. Methods: This retrospective study used data obtained from clinical records. Patients older than 18 years with decompensated HF whose complete clinical records included the variables of interest were included. Patients were classified according to the presence or absence of diuretic resistance. Bivariate and multivariate analyses were performed to evaluate factors associated with diuretic resistance. Results: A total of 76 patients were analyzed, and the frequency of diuretic resistance was 35.5% (n = 27). In bivariate analysis, type 2 diabetes mellitus, chronic kidney disease, elevated creatinine, urea, blood urea nitrogen (BUN), and urine protein levels, decreased glomerular filtration rate (GFR) and serum albumin, and prior treatment with nonsteroidal anti-inflammatory drugs (NSAIDs) and angiotensin-converting enzyme inhibitors/angiotensin II receptor antagonists (ACEI/AARII) were significantly associated with diuretic resistance. In the multivariate logistic regression model, prior ACEI/AARII treatment, history of type 2 diabetes mellitus, BUN levels, and serum albumin levels remained independently associated with diuretic resistance classification. Conclusions: Diuretic resistance was frequent in this cohort of patients hospitalized with decompensated heart failure, and several clinical and biochemical factors were independently associated with its occurrence. These findings may help identify patients at higher risk of diuretic resistance, although they should be confirmed in future prospective studies. Full article

Research on oxazolones, particularly 4-alkynyloxazolones, has garnered increasing interest due to the presence of an alkynyl group, which facilitates molecular conjugation and enables diverse chemical modifications. In this study, three representative 4-alkynyloxazolone derivatives (L1–L3) were synthesized and structurally characterized through single-crystal X-ray diffraction and computational analysis to obtain a reliable structure of L1–L3 to subsequently predict in silico interactions with the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike glycoprotein. The crystallographic results revealed high molecular planarity and multifurcated hydrogen bonding. Considering the obtained crystallographic structure, theoretical descriptors such as HOMO–LUMO energy gaps and electrostatic potential maps indicated that these compounds exhibit favorable electronic reactivity, particularly for L3, with favorable drug-like predictions. The lack of methoxy groups in L2 and L3 makes these compounds have lower predicted toxicity parameters than L1. Molecular docking calculations targeting SARS-CoV-2 spike glycoprotein in three different feasible conformations in a biological matrix, i.e., three receptor-binding domains (RBD) in down conformation, two RBD in down and one in up conformation, as well as RBD bound to the human receptor angiotensin-converting enzyme 2 (ACE2), suggested strong binding affinities and specific interactions with the RBD moiety, mainly in the up conformation. Overall, this work integrates crystallographic and computational approaches to establish the structural and in silico evaluation of spike-binding properties of early substituted 4-alkynyloxazolones, suggesting L3 as a candidate for future in vitro antiviral assays. Full article

Cardiovascular disease (CVD) is a leading cause of morbidity and mortality globally among older adults. Similar to humans, age-related declines in cardiac function are observed in C57BL/6 mice. Angiotensin-converting enzyme 2 (ACE2), a key component of the renin–angiotensin system (RAS), counteracts detrimental RAS effects by converting angiotensin II (Ang II) to angiotensin-(1-7) (Ang-(1-7)), thereby playing a critical role in mitigating CVD pathogenesis. Here, we utilized transgenic K18-hACE2 mice to investigate the protective effects of ACE2 against cardiac aging. Histological and morphometric analyses revealed significant reductions in heart weight and improvements in cardiac structure in K18-hACE2 mice compared to wild-type controls. Furthermore, aged C57BL/6 mice exhibited progressive cardiac aging phenotypes, including mitochondrial dysfunction, telomere shortening, and immune dysregulation—all of which were significantly attenuated in K18-hACE2 mice. These findings demonstrate the protective role of ACE2 in cardiac aging and highlight its potential as a therapeutic target for anti-aging interventions. Full article

Background: In patients with type 2 diabetes mellitus (T2DM), angiotensin-converting enzyme inhibitors (ACE-Is) and angiotensin receptor blockers (ARBs) are first-line antihypertensive treatments with important cardiovascular benefits, but their impacts on coronary-specific inflammation are unknown. Pericoronary adipose tissue (PCAT) attenuation, as assessed by coronary computed tomography angiography (CCTA), serves as a specific biomarker for coronary inflammation. Here, we aim to assess whether treatment with ACE-I or ARB is correlated with lower PCAT attenuation. Methods: In this retrospective observational study, we analyzed 223 patients with T2DM and coronary atherosclerosis who underwent CCTA from 1 January 2017 to 1 September 2024 at our institution. PCAT attenuation was measured in the proximal right coronary artery. Propensity score matching and multivariate linear regression analyses were performed for comparisons. Results: Of the 223 patients (mean age of 64.9 ± 8.8 years, 69.1% male), 122 patients were on ACE-I or ARB (ACE-I/ARB). ACE-I/ARB users had similar PCAT attenuation as their counterparts after propensity score matching (−72.1 ± 7.5 and −71.7 ± 8.1 HU, respectively; p = 0.722). Subgroup analysis in patients with glomerular filtration rate (GFR) < 90 mL/min revealed lower PCAT attenuation in ACE-I/ARB users (−74.8 ± 6.6 vs. −71.4 ± 7.1 HU; p = 0.038), with a significant interaction between these two factors in the multivariate analysis (p = 0.047). Other antihypertensive treatments (beta blockers, dihydropyridine calcium channel blockers, and thiazides) were not linked with lower coronary inflammation. Conclusions: In T2DM patients with coronary atherosclerosis, we did not find an association between ACE-I/ARB treatment and lower coronary inflammation as defined by PCAT attenuation, although such a relationship may exist in those with reduced GFRs. Full article

The renin–angiotensin system (RAS) regulates inflammation, tissue homeostasis, and barrier integrity in lung and colon epithelial cells. Beyond classical pathways, non-canonical components including angiotensin-converting enzyme 2 (ACE2), epidermal growth factor receptor (EGFR), insulin-like growth factor 2 receptor (IGF2R) and aminopeptidase N (ANPEP) are implicated in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections and bacterial sepsis due to their roles in tissue repair and signaling. Despite their similar inflammatory and coagulopathic features, their impact on RAS-associated non-immune gene expression in epithelial tissues remains unclear. This study investigates the regulation of these targets in lung (BEAS-2B) and colon (CRL-1831) cells following exposure to recombinant SARS-CoV-2 spike protein N-terminal domain fragment (S1-NTD) and Pseudomonas aeruginosa-derived lipopolysaccharide (LPS). Cells were treated with 100 ng/mL of S1-NTD or LPS for 12–72 h. Viability was assessed via XTT assays, and molecular changes were analyzed through qRT-PCR and Western blotting. Both stimuli induced a time and dose-dependent decrease in metabolic activity. ACE2 was significantly downregulated in lung cells, while transient upregulation occurred in colon cells at 24 h. EGFR expression increased in colon cells following LPS exposure but decreased in lung cells after S1-NTD treatment. Both IGF2R and ANPEP were upregulated by S1-NTD in lung cells at 72 h, whereas colon cells showed earlier upregulation at 24–48 h. Our findings reveal that viral and bacterial stimuli elicit distinct, tissue-specific regulatory patterns in RAS-associated pathways. These alterations may contribute to epithelial barrier dysfunction and inflammation, highlighting these proteins as potential targets for managing secondary bacterial infections and inflammatory lung–gut complications in COVID-19. Full article

Periodontitis (P) and Type 2 Diabetes Mellitus (T2DM) are chronic inflammatory diseases that share pathophysiological pathways involving immune dysregulation and oxidative stress. Both conditions have been associated with increased susceptibility to viral infections, including SARS-CoV-2. In this regard, molecules associated with viral infection include angiotensin-converting enzyme 2 (ACE2) and transmembrane serine protease 2 (TMPRSS2). This study aimed to evaluate the clinical periodontal status, oral microbiota composition, and the expression of ACE2 and TMPRSS2 in the oral epithelium and gingival tissue of patients with and without T2DM and P. Methods: This cross-sectional study enrolled 120 participants allocated into four groups based on periodontal and glycemic status: periodontally healthy non-diabetic individuals (PH non-T2DM), periodontitis without diabetes (P non-T2DM), periodontally healthy individuals with type 2 diabetes mellitus (PH T2DM), and periodontitis with T2DM (P T2DM), with 30 participants per group. Full-mouth clinical periodontal parameters were recorded by a calibrated examiner. Oral microbiota was assessed from unstimulated whole saliva, labial swab samples, and subgingival biofilm by selective culture and checkerboard DNA-DNA hybridization. Gingival exfoliative cytology and full-thickness gingival biopsies were obtained for immunohistochemical evaluation of ACE2 and TMPRSS2 expression. Cytomorphometric analysis and polymorphonuclear cell counts were performed on epithelial smears. Additionally, primary human gingival fibroblasts (HGFs) isolated from each group were stimulated with bacterial ligands (LPS, LTA, and PGN) to assess ACE2 and TMPRSS2 modulation by Western blot. Intergroup comparisons were performed using one-way ANOVA with Bonferroni post hoc correction and the Mann–Whitney U test, with statistical significance set at p < 0.05. Results: Diabetic patients exhibited higher plaque accumulation, clinical attachment loss, and bleeding on probing compared with non-diabetic individuals (p < 0.05). The diabetic groups showed significantly higher levels of Actinomyces, Fusobacterium, and Streptococcus spp., with decreased Staphylococcus counts. ACE2 and TMPRSS2 expression were markedly elevated in gingival epithelial cells of P T2DM patients, predominantly in basal and suprabasal layers. The nuclear-to-cytoplasmic ratio and polymorphonuclear cell counts were also increased in diabetic subjects. Conclusions: T2DM and P synergistically upregulate ACE2 and TMPRSS2 expression and alter the oral microbiota. Full article

Hierarchical functionalisation of the UiO-66(Zr)-NH₂ metal–organic framework with cysteine, poly(ethylene glycol) (PEG), and the SARS-CoV-2 spike receptor-binding domain (RBD) was developed to enable receptor-specific interaction with the angiotensin-converting enzyme 2 receptor (ACE2) in model cells. Post-synthetic modification using cysteine and heterobifunctional PEG linkers allowed controlled bioconjugation of SpyTag-labelled RBD via SpyTag/SpyCatcher chemistry, while preserving the crystallinity, microporosity, and intrinsic optical properties of the UiO-66(Zr)-NH₂ framework. Comprehensive physicochemical characterisation confirmed successful surface functionalisation, tunable aggregation behaviour, and retention of multimodal optical characteristics. Cellular studies in HEK293T and HeLa cells overexpressing EGFP-tagged ACE2 demonstrated enhanced and selective association and uptake of RBD-functionalised nanoparticles compared with non-targeted analogues. Multimodal fluorescence imaging, fluorescence lifetime imaging microscopy, flow-cytometry, and electron microscopy indicated ACE2-dependent endocytic internalisation, with predominant localisation in endosomal and autophagosomal compartments, while both amine- and cysteine-modified formulations exhibited good biocompatibility. Overall, this study establishes a virus-mimetic, ACE2-targeted UiO-66(Zr)-based nanosystem as a proof-of-concept biointerface platform for receptor-specific cellular delivery and imaging, providing a foundation for future MOF-based nanocarriers exploiting ligand–receptor interactions. Full article

Gut microbiome composition influences cardiovascular drug efficacy and safety, yet its integration into heart failure (HF) management remains underexplored. Alterations in intestinal microbial communities have been linked to atherosclerosis, coronary artery disease, heart failure, and hypertension through multiple mechanisms. Dysbiosis disrupts the balance between commensal and pathogenic bacterial species, impairing gut barrier function and activating inflammatory pathways. The altered microbial ecosystem modulates the production of key metabolites—such as trimethylamine-N-oxide (TMAO), short-chain fatty acids (SCFAs), and secondary bile acids (BAs)—that directly impact cardiovascular function. This narrative review synthesizes current evidence on bidirectional interaction between heart failure pharmacotherapy and gut microbiome composition. Commonly used drugs in heart failure management show microbiome-dependent pharmacokinetics. Digoxin undergoes bacterial inactivation by Eggerthella lenta, while angiotensin converting enzyme inhibitors and beta-blockers demonstrate enhanced efficacy with specific Firmicutes populations. Conversely, certain probiotic strains attenuate drug-induced gut barrier injury and restore gut homeostasis. Sodium–glucose cotransporter 2 inhibitors (SGLT2i), mineralocorticoid receptor antagonists, and angiotensin receptor–neprilysin inhibitors exhibit beneficial microbiome-modulating effects beyond their primary cardiovascular actions. These findings underscore the potential for microbiome-informed precision medicine in heart failure. However, significant methodological challenges must be addressed, including lack of standardization in microbiome profiling, small sample sizes, and limited longitudinal data. Future research should focus on identifying specific microbial signatures that predict drug response, developing targeted probiotic interventions, and conducting prospective clinical trials to validate pharmacomicrobiomics approaches in heart failure management. Full article

Salivary gland infection by SARS-CoV-2 requires viral entry via routes and mechanisms that remain unresolved. This study examined the expression of the angiotensin-converting enzyme 2 (ACE2) receptor in salivary tissues and basal cell-derived human salivary progenitor cells (hS/PCs), an unstudied potential entry point for SARS-CoV-2. Multiple detection modalities, including immunocytochemistry, Western blotting, flow cytometry and RT-PCR, demonstrated a consistent lack of ACE2 protein and transcript in both tissue specimens and primary salivary epithelial cells. Antigen retrieval at pH 9 was determined to be optimal for immunodetection protocols, yet ACE2 remained undetectable. Small intestine tissue served as a positive control, confirming the validity of the methods and reagents we used. Considering there can be other receptors for SARS-CoV-2, flow cytometric analyses demonstrated that recombinant SARS-CoV-2 spike protein failed to bind to salivary epithelial cells, in contrast to HEK293 cells engineered to overexpress ACE2, which showed robust spike binding. Additional studies showed that patient-derived salivary cells, negative for ACE2, are not infected by the SARS-CoV-2 pseudovirus, while ACE2-positive cells are readily infected. These findings strongly support our conclusion that salivary cells do not serve as major targets for SARS-CoV-2 infection via ACE2, spike protein, or an alternate receptor. Thus, salivary cells are unlikely major targets for SARS-CoV-2 infection, either through direct exposure to viral particles in ductal fluids or via access to basal cells across the basement membrane. Full article

Background/Objectives: While the functions of angiotensin-converting enzyme (ACE) 1 and 2 are well established in peripheral tissues, the role of the spinal ACE1 and ACE2 pathways in the development of neuropathic pain remains unclear. This study examined the role of the spinal ACE1 and ACE2 pathways in trigeminal neuropathic pain produced by inferior alveolar nerve (IAN) injury. Methods: The experiments were conducted using male Sprague-Dawley rats (6–8 weeks old, weighing 220–250 g). The left mandibular second molar was extracted, and a dental mini-implant was placed to induce IAN injury. IAN injury produced robust and long-lasting mechanical allodynia and markedly increased angiotensinogen (AGT) expression within the ipsilateral trigeminal subnucleus caudalis (iTSC). Results: Neuropathic mechanical allodynia was inhibited by intracisternally administered losartan (an angiotensin II type-1 receptor antagonist), but not by an angiotensin II type-2 receptor antagonist. Intracisternal treatment with captopril (an ACE1 inhibitor) and diminazene aceturate (an ACE2 activator) produced significant anti-allodynic effects. Intracisternally injected angiotensin-(1-7) reduced neuropathic mechanical allodynia, and this anti-allodynic effect was blocked by pretreatment with A779, a Mas receptor inhibitor. In naïve rats, the intracisternal administration of DX600 (an ACE2 inhibitor) resulted in mechanical allodynia, which was inhibited by intracisternal pretreatment with losartan. IAN injury led to upregulated ACE1 expression and downregulated ACE2 expression in the iTSC. Conclusions: Our findings indicate that IAN injury induces a polarized shift in the ACEs within the iTSC, characterized by increased ACE1 and decreased ACE2 expression. Their modulation may therefore offer a promising strategy for developing effective treatments for chronic pain. Full article

Angiotensin-converting enzymes (ACE and ACE2) are key components of the renin–angiotensin–aldosterone system (RAAS) and are present in the gastrointestinal tract and intestinal content, preserving their catalytic activity, and may interact with the gut microbiota. The present study aimed to determine the origin of fecal ACE and ACE2 activity. Fecal pellets from germ-free, ACE and ACE2 knockout (KO) mice, and from the corresponding controls were analyzed using fluorimetric enzyme activity assays. ACE activity was assessed using Hippuryl-His-Leu and Z-Phe-His-Leu as substrates; ACE2 activity was assessed using Mca-APK (Dnp), with and without the ACE2 inhibitor MLN-4760. Germ-free mice showed increased fecal ACE and ACE2 activity compared to controls. ACE2-KO mice lacked fecal ACE2 activity, whereas ACE activity was unaffected. In ACE-KO mice, fecal ACE activity was reduced, but not abolished, while ACE2 activity remained similar to controls. In ACE C- and N-domain KO mice, ACE activity was similar to controls, and inhibition with captopril completely abolished fecal ACE activity using Hippuryl-His-Leu, but not Z-Phe-His-Leu, in those animals. These findings indicate that fecal ACE and ACE2 activity results from combined intestinal shedding and microbiota-related mechanisms, supporting a modulatory role of the gut environment on luminal RAAS activity. Full article

Background: The renin-angiotensin system (RAS), traditionally known for its role in cardiovascular regulation, has also emerged as a key regulator of tumor progression and metastasis. Dysregulation of the RAS components has been implicated in breast cancer due to the significant presence of the RAS-related proteins in the breast tissue. This study aims to identify the dysregulated RAS components and investigate their potential as candidate biomarkers. Methods: A pilot case–control study was carried out with 21 treatment-naïve breast cancer patients and 17 healthy controls. Plasma levels of Ang 1-7, Ang II, ACE2 and selected cytokines (IL-6, IL-8, IL-10 and IFN-γ) were measured using LC-MS/MS and ELISA. ROC curves were used to assess changes in biomarker levels across the RAS components. Results: This pilot cohort showed evidence of altered circulating RAS-related analytes and IL-10 in treatment-naïve breast cancer patients compared with controls. The ratio of Ang 1-7/Ang II was reduced by over two-fold in breast cancer patients (p = 0.0442). While plasma ACE2 was significantly elevated in breast cancer patients (p = 0.0005), IL-10 was significantly suppressed (p = 0.0420). In exploratory logistic regression analysis, ACE2 showed potential as a classifier with improved discrimination when combined with Ang 1-7 and Ang II (AUC = 0.9396 [95% bootstrap CI: 0.84–1.00], accuracy = 92.59% at the Youden-optimized threshold). However, due to the small sample size and methodological limitations, these findings require further validation. Conclusions: In this exploratory pilot study, plasma ACE2, the Ang 1-7/Ang II ratio, and IL-10 showed promising discriminatory performance. However, these findings are hypothesis-generating and require external validation in larger, prospectively enrolled cohorts before any clinical inference can be drawn. Full article

Background: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infects host cells through the interaction between the spike protein receptor-binding domain (RBD) and the human angiotensin-converting enzyme 2 (hACE2) receptor, which is expressed on epithelial cells in various tissues, including the respiratory tract. Therefore, mucosal immunity in the respiratory tract plays a key role in protection against viral infection. Previously, we demonstrated that intranasal administration of antigens (Ags) conjugated with the M cell-targeting peptide Co4B enhances both mucosal and systemic immune responses. That conjugation with human β-defensin 2 (HBD2) increases neutralizing antibody (Ab) responses. Methods: A recombinant antigen conjugate incorporating both Co4B and HBD2 was designed to enhance immunogenicity. Its immunogenicity was evaluated in mice following intranasal immunization. Antigen-specific antibody responses were measured in serum and bronchoalveolar lavage fluid. T-cell responses were evaluated in lungs and spleens. Protective efficacy was assessed using SARS-CoV-2-susceptible hACE2 knock-in mice. Results: Ag-specific Ab levels increased in both serum and bronchoalveolar lavage fluid of mice immunized intranasally with the conjugate. Especially, T-cell responses were significantly enhanced in the lungs and spleens of immunized hACE2 knock-in mice. In challenge experiments, intranasal administration of the conjugate reduced viral load. Moreover, Siglec F was identified as a potential receptor for Co4B, a previously uncharacterized M cell-targeting ligand. Conclusions: A recombinant viral Ag containing Co4B and HBD2 induces virus-specific humoral and cellular immune responses. Although further optimization of the vaccine formulation and administration strategy is needed, this conjugate shows potential as a platform for improving mucosal and systemic immunity. Full article

Angiotensin-converting enzyme (ACE) inhibitors (ACEis) are one of the most successful drug classes for the treatment of hypertension and the prevention of its cardiovascular complications. ACE activates the pressor hormone angiotensin but also inactivates the vasodilator peptide bradykinin (BK). A rare side effect of ACEis, angioedema (AE), has been proposed to result from pro-inflammatory effects of BK. Novel considerations are offered in this debate: (1) the bradykinin B2 receptor antagonist icatibant has had an inconsistent effect on ACEi-associated AE, but its potency and duration of action are much inferior to those of a novel nonpeptide antagonist of this receptor, deucrictibant. (2) Tissue kallikrein (KLK-1) is an effective kininogenase, particularly abundant in the salivary glands, possibly related to orofacial presentation of ACEi-induced AE. (3) The strongly regulated human kinin B1 receptor, optimally responsive to Lys-des-Arg⁹-BK, is functionally compartmentalized with KLK-1 which produces Lys-BK from kininogens. Chronic treatment with ACEi drugs in laboratory animals induces the expression of vascular B1R that mediates vasodilation. Therefore, ACEi-AE may be largely or completely initiated by KLK-1. Inhibitors of this protease or combined antagonists of both kinin receptor subtypes may be useful for the management of this condition. Full article

One of the most critical aspects of post-acute COVID-19 syndrome (PACS) and post-acute COVID-19 vaccination syndrome (PACVS) is the presence of autoantibodies. These autoantibodies are directed against various receptors in the autonomic and cardiovascular systems, including those targeting proteins of the renin–angiotensin system (RAS). The RAS plays a central role in regulating vascular homeostasis, inflammation, and endothelial function. During SARS-CoV-2 infection, the interaction of the spike (S) protein with angiotensin-converting enzyme 2 (ACE2) can alter the balance of the RAS, favoring an imbalance towards the ACE/Angiotensin II/AT1R axis, known for its pro-inflammatory, pro-thrombotic, and vasoconstrictive properties. Similar pathological mechanisms also come into play in response to vaccinations that use the S protein as an antigen. Studies conducted by other groups and us on patients with PACS and PACVS have revealed the presence of autoantibodies directed against these RAS components and the mechanisms by which these antibodies can worsen the clinical situation. In particular, anti-ACE2, presumably formed by the anti-idiotype network or molecular mimicry, is correlated with PACVS symptoms in many patients. Furthermore, the presence of anti-MAS1 antibodies can reduce the efficiency of the ACE2/Angiotensin-(1–7)/MAS1 axis, which normally acts as a counter-regulator. Considering this evidence, an analysis of RAS molecules and the autoantibodies implicated in reactions to them may be useful for evaluating a state of persistent dysregulation associated with post-vaccination symptoms such as asthenia, headache, skin edema and bruising, cardiovascular alterations, and neurovegetative manifestations. Finally, we offer insights into diagnosing these multifaceted syndromes and working hypotheses to guide research into possible therapeutic approaches. Full article