Angiotensin-converting Enzyme Levels Research Articles

Predicting susceptibility to COVID-19 infection in patients on maintenance hemodialysis by cross-coupling soluble ACE2 concentration with lymphocyte count: an algorithmic approach

IntroductionPatients on maintenance hemodialysis (MHD) were more vulnerable to and had a higher mortality during the COVID-19 pandemic. As angiotensin converting enzyme 2 (ACE2) and transmembrane protease serine S1 member 2 (TMPRSS2) played crucial roles in viral entry into the human host cells, we therefore investigated in the MHD patients whether their plasma levels were associated with susceptibility to the COVID-19.MethodsBlood samples were collected from the patients in our then COVID-19 free center immediately upon lifting of the stringent quarantine measures in early December of 2022 and infection situation was observed within the following 2 weeks. Plasma levels of the soluble ACE2 (sACE2), ACE (sACE) and TMPRSS2 (sTMPRSS2) were measured with ELISA method. Data were stepwisely tested for independent effect, relevant role and synergistic action on the susceptibility by multiple logistic regression, receiver operating characteristic curve and multiple dimensionality reduction (MDR) method, respectively.ResultsAmong the 174 eligible patients, 95 (54.6%) turned COVID-19 positive with a male to female ratio of 1.57 during the observation period. Comparing with the uninfected, the infected had significantly higher sACE2 and lower sTMPRSS2 levels upon comparable sACE concentration. Besides the sACE2, factors associated with susceptibility were vintage and individual session time of the hemodialysis, smoking and comorbidity of hepatitis, whereas lymphocyte counts showed a tendency (p = 0.052). Patients simultaneously manifesting higher sACE2 level and lower lymphocyte counts had an increased infection risk as confirmed by the MDR method.ConclusionBy sorting out the susceptible ones expeditiously, this algorithmic approach may help the otherwise vulnerable MHD patients weather over future wave of COVID-19 variants or outbreak of other viral diseases.

Apelin from Perivascular Adipose Tissue Is Involved in the Regulation of Vasorelaxation and Renal Function in Metabolic Syndrome

The perivascular adipose tissue (PVAT) regulates the arterial tone by releasing vasoactive molecules. PVAT dysfunction favoring the vasorelaxation response could contribute to the development of kidney disease in metabolic syndrome (MetS). Previously, we demonstrated that overactivation of angiotensin II signaling in the PVAT deteriorates the compensatory PVAT effects in rats with MetS (SHRSP.Z-Leprfa/IzmDmcr (SPZF) and SHR/NDmcr-cp (CP) rats). Apelin is an endogenous regulator of angiotensin II. Therefore, we investigated whether changes in apelin levels in the PVAT alter PVAT function and impair kidney function in MetS. Twenty-three-week-old male and female SPZF and CP rats were used. In the female CP rats, apelin mRNA levels in renal arterial PVAT, enhancing effects of the PVAT on acetylcholine-induced relaxation in renal arteries, and estimated glomerular filtration rate (eGFR) were the highest, and urine protein levels and homeostasis model assessment of insulin resistance (HOMA-IR) were the lowest. Apelin mRNA levels were positively correlated with the enhancing effects of the PVAT on vasorelaxation and eGFR but negatively correlated with urine protein levels and HOMA-IR. Moreover, apelin levels positively correlated with mRNA levels of angiotensin-converting enzyme 2 and angiotensin II type 1 receptor-associated protein, which are negative regulators of angiotensin II. This study suggests that a decline in apelin levels in the PVAT, probably owing to angiotensin II, is associated with PVAT dysfunction on vascular tone, resulting in impaired kidney function in MetS.

Effect of ertugliflozin on left ventricular function in type 2 diabetes and pre-heart failure: the Ertu-GLS randomized clinical trial

BackgroundThe therapeutic effects of ertugliflozin, a sodium-glucose cotransporter 2 inhibitor, on cardiovascular outcome are not fully understood. This study aimed to evaluate the efficacy and safety of ertugliflozin on cardiac function in people with type 2 diabetes and pre-heart failure.MethodsWe conducted a 24-week randomized, double-blind, placebo-controlled trial involving individuals with type 2 diabetes inadequately controlled with antidiabetic medications. Participants with left ventricular hypertrophy, E/e’ >15, or impaired left ventricular global longitudinal strain (LVGLS) were randomized 1:1 to receive either ertugliflozin (5 mg once daily) or a placebo. The primary outcome was the change in LVGLS. Secondary outcomes included changes in left ventricular mass index (LVMI) and left ventricular ejection fraction (LVEF). Prespecified exploratory outcomes, including angiotensin-converting enzyme 2 (ACE2) and angiotensin (1–7) levels, were also assessed.ResultsA total of 102 individuals (mean age, 63.9 ± 9.2 years; 38% women) were included. The ertugliflozin group showed a significant improvement in LVGLS (− 15.5 ± 3.1% to − 16.6 ± 2.8%, P = 0.004) compared to the placebo group (− 16.7 ± 2.7% to − 16.4 ± 2.6%, P = 0.509), with a significant between-group difference (P = 0.013). Improvements in LVMI and LVEF were also observed. Additionally, significant reductions in HbA1c, systolic blood pressure, whole-body and visceral fat, uric acid, proteinuria, N-terminal pro–B-type natriuretic peptide, and lipoprotein(a) were noted. ACE2 and angiotensin (1–7) levels significantly increased in the ertugliflozin group compared to the placebo group and correlated with changes in LVGLS [r = 0.456, P < 0.001 for ACE2; r = 0.541, P < 0.001 for angiotensin (1–7)]. Adverse events were similar between the two groups.ConclusionsThis study demonstrated that ertugliflozin has beneficial effects on left ventricular function in individuals with type 2 diabetes and pre-heart failure, and it provided insights into potential underlying mechanisms.Clinical trial registration ClinicalTrials.gov Identifier: NCT03717194.

Unveiling the Interplay-Vitamin D and ACE-2 Molecular Interactions in Mitigating Complications and Deaths from SARS-CoV-2.

The interaction of the SARS-CoV-2 spike protein with membrane-bound angiotensin-converting enzyme-2 (ACE-2) receptors in epithelial cells facilitates viral entry into human cells. Despite this, ACE-2 exerts significant protective effects against coronaviruses by neutralizing viruses in circulation and mitigating inflammation. While SARS-CoV-2 reduces ACE-2 expression, vitamin D increases it, counteracting the virus's harmful effects. Vitamin D's beneficial actions are mediated through complex molecular mechanisms involving innate and adaptive immune systems. Meanwhile, vitamin D status [25(OH)D concentration] is inversely correlated with severity, complications, and mortality rates from COVID-19. This study explores mechanisms through which vitamin D inhibits SARS-CoV-2 replication, including the suppression of transcription enzymes, reduced inflammation and oxidative stress, and increased expression of neutralizing antibodies and antimicrobial peptides. Both hypovitaminosis D and SARS-CoV-2 elevate renin levels, the rate-limiting step in the renin-angiotensin-aldosterone system (RAS); it increases ACE-1 but reduces ACE-2 expression. This imbalance leads to elevated levels of the pro-inflammatory, pro-coagulatory, and vasoconstricting peptide angiotensin-II (Ang-II), leading to widespread inflammation. It also causes increased membrane permeability, allowing fluid and viruses to infiltrate soft tissues, lungs, and the vascular system. In contrast, sufficient vitamin D levels suppress renin expression, reducing RAS activity, lowering ACE-1, and increasing ACE-2 levels. ACE-2 cleaves Ang-II to generate Ang(1-7), a vasodilatory, anti-inflammatory, and anti-thrombotic peptide that mitigates oxidative stress and counteracts the harmful effects of SARS-CoV-2. Excess ACE-2 molecules spill into the bloodstream as soluble receptors, neutralizing and facilitating the destruction of the virus. These combined mechanisms reduce viral replication, load, and spread. Hence, vitamin D facilitates rapid recovery and minimizes transmission to others. Overall, vitamin D enhances the immune response and counteracts the pathological effects of SARS-CoV-2. Additionally, data suggests that widely used anti-hypertensive agents-angiotensin receptor blockers and ACE inhibitors-may lessen the adverse impacts of SARS-CoV-2, although they are less potent than vitamin D.

12268 Hypercalcemia Alert: Exploring The Link To Isolated Bone Marrow Sarcoidosis

Abstract Disclosure: M. Renzu: None. C.M. Hubers: None. V. mehta: None. A. Qazi: None. D.K. Yerasuri: None. Introduction: Sarcoidosis, a complex disorder marked by granuloma formation in diverse organs, often affects the lungs, but can involve various systems as well. Rare cases of bone marrow involvement may mimic conditions like multiple myeloma, emphasizing the need to consider sarcoidosis in patients with bone marrow abnormalities, especially those without typical myeloma features. Case Presentation: A 79-year-old white male with a medical history of hypertension, hyperlipidemia, deep venous thrombosis, prostate cancer in remission, chronic knee pain, and basal cell carcinoma presented for pre-operative evaluation, as he was scheduled for an elective orthopedic procedure. On routine lab work, he was found to have acute hypercalcemia and normocytic anemia. This finding raised suspicion for an underlying systemic pathology. He reported that he did not take any calcium or vitamin D supplements at home. Subsequent endocrine assessment, including evaluation of parathyroid hormone and vitamin D levels, revealed a non-PTH-mediated hypercalcemia. The persistence of hypercalcemia prompted further investigations, including assessments for multiple myeloma by oncology. The workup was negative for multiple myeloma but significant for granulomas on bone marrow biopsy, a finding consistent with sarcoidosis. Additionally, angiotensin converting enzyme levels were elevated at the time of diagnosis. Interventions led to the resolution of hypercalcemia following steroid therapy of prednisone 20 mg daily and close follow up with endocrinology. As part of his follow up, ACE levels are being regularly monitored, with the patient going for lab work every other month. Discussion: Bone marrow biopsies rarely reveal granulomas and sarcoidosis accounts for only a very small percentage of these findings. The standard workup for sarcoidosis typically does not include bone marrow biopsies. By integrating biopsies into the standard diagnostic protocol researchers may gain insights into the etiology and mechanisms driving this manifestation of sarcoidosis, ultimately improving diagnostic accuracy and patient care. Distinguishing sarcoidosis from multiple myeloma also poses diagnostic challenges, necessitating thorough evaluation in patients with bone marrow abnormalities. Despite its rarity, clinical suspicion for sarcoidosis should be considered in patients with underlying hematologic disorders or malignancies. Additionally, sarcoidosis exhibits geographical variation, being less common in Japanese men and more prevalent in African American women. This highlights the importance of considering demographic factors when evaluating patients for sarcoidosis and its extrapulmonary manifestations. Long-term outcomes in isolated bone marrow sarcoidosis remain unclear, warranting surveillance for progression to multiple myeloma or other lymphoproliferative disorders. Presentation: 6/2/2024

6564 A Case of Severe Hypercalcemia in Carney's Complex

Abstract Disclosure: J. Chippior: None. M. Rayan: None. L. Wright: None. L.S. Kirschner: Grant Recipient; Self; Medpace, Sparrow, Corcept Therapeutics, Corcept, Spruce, CinCor, Crinetics, Adrenas. S.W. Ing: Grant Recipient; Self; Alexion Pharmaceuticals, Inc., Amgen Inc, Radius Health, Inc, Takeda, Ultragenyx, Amolyt, Bridge Bio. Carney complex is a rare syndrome with fewer than 750 reported cases, characterized by lentigniosis, myxomas, and the occurrence of both endocrine and non-endocrine tumors. An inactivating mutation PRKAR1A, which encodes for the type 1A regulatory subunit of Protein kinase A, is responsible for over 70% of familial cases and 37% of sporadic cases. A 31-year-old female with a history of Carney complex, Cushing syndrome due to primary pigmented nodular adrenocortical disease (PPNAD), facial lentigines, spinal Schwannomas, and recent ischemic stroke secondary to embolization of a cardiac atrial myxoma, was transferred to our medical center for hyperemesis and severe hypercalcemia. Albumin-corrected serum calcium measured 15.4 mg/dL (8.6-10.5 mg/dL), ionized calcium 7.8 mg/dL (4.6-5.3 mg/dL) associated with suppressed PTH, normal PTH-related protein, and elevated bone turnover markers, C-telopeptide 4,273 pg/ml (150-635) and Procollagen Type 1 N-terminal Propeptide 222 mcg/L (19-83). Evaluation for etiology of hypercalcemia revealed elevated 1,25 dihydroxy vitamin D at 107.0 pg/ml (20-79) and elevated interleukin-6 at 11 pg/ml (&amp;lt;6.4). IL-6 is expressed by cardiac myxomas. Serum angiotensin-converting enzyme level was 50 U/L (16-85) and infectious workup was negative for potential granulomatous causes of elevated calcitriol (including testing for tuberculosis, histoplasma, blastomyces, bartonella, and coccidioides). CT angiogram of the abdomen and pelvis (completed in preparation of atrial myxoma resection) revealed ground-glass opacities in bilateral posterior lung fields and multiple pulmonary nodules, with the largest measuring 8 mm. After treatment with aggressive intravenous fluid resuscitation, intramuscular calcitonin, and intravenous zoledronic acid, corrected calcium normalized to 9.4 mg/dL at discharge. Urinary cortisol was 6.2 mcg per 24-hr (3.5-45), for which she started hydrocortisone 20 mg daily to treat suspected adrenal insufficiency as excess cortisol secretion in PPNAD may be episodic. Thus remission of hypercortisolism may have unmasked an underlying hypercalcemia, and adrenal insufficiency itself may have contributed to this finding. She had excision of left atrial myxoma and has continued to exhibit normal calcium levels on steroid replacement therapy. Repeat chest CT to further characterize these pulmonary findings is planned. This case illustrates a unique constellation of endocrine features associated with severe hypercalcemia in Carney complex. Presentation: 6/1/2024

6564 A Case Of Severe Hypercalcemia In Carney's Complex

Abstract Disclosure: J. Chippior: None. M. Rayan: None. L. Wright: None. L.S. Kirschner: Grant Recipient; Self; Medpace, Sparrow, Corcept Therapeutics, Corcept, Spruce, CinCor, Crinetics, Adrenas. S.W. Ing: Grant Recipient; Self; Alexion Pharmaceuticals, Inc., Amgen Inc, Radius Health, Inc, Takeda, Ultragenyx, Amolyt, Bridge Bio. Carney complex is a rare syndrome with fewer than 750 reported cases, characterized by lentigniosis, myxomas, and the occurrence of both endocrine and non-endocrine tumors. An inactivating mutation PRKAR1A, which encodes for the type 1A regulatory subunit of Protein kinase A, is responsible for over 70% of familial cases and 37% of sporadic cases. A 31-year-old female with a history of Carney complex, Cushing syndrome due to primary pigmented nodular adrenocortical disease (PPNAD), facial lentigines, spinal Schwannomas, and recent ischemic stroke secondary to embolization of a cardiac atrial myxoma, was transferred to our medical center for hyperemesis and severe hypercalcemia. Albumin-corrected serum calcium measured 15.4 mg/dL (8.6-10.5 mg/dL), ionized calcium 7.8 mg/dL (4.6-5.3 mg/dL) associated with suppressed PTH, normal PTH-related protein, and elevated bone turnover markers, C-telopeptide 4,273 pg/ml (150-635) and Procollagen Type 1 N-terminal Propeptide 222 mcg/L (19-83). Evaluation for etiology of hypercalcemia revealed elevated 1,25 dihydroxy vitamin D at 107.0 pg/ml (20-79) and elevated interleukin-6 at 11 pg/ml (&amp;lt;6.4). IL-6 is expressed by cardiac myxomas. Serum angiotensin-converting enzyme level was 50 U/L (16-85) and infectious workup was negative for potential granulomatous causes of elevated calcitriol (including testing for tuberculosis, histoplasma, blastomyces, bartonella, and coccidioides). CT angiogram of the abdomen and pelvis (completed in preparation of atrial myxoma resection) revealed ground-glass opacities in bilateral posterior lung fields and multiple pulmonary nodules, with the largest measuring 8 mm. After treatment with aggressive intravenous fluid resuscitation, intramuscular calcitonin, and intravenous zoledronic acid, corrected calcium normalized to 9.4 mg/dL at discharge. Urinary cortisol was 6.2 mcg per 24-hr (3.5-45), for which she started hydrocortisone 20 mg daily to treat suspected adrenal insufficiency as excess cortisol secretion in PPNAD may be episodic. Thus remission of hypercortisolism may have unmasked an underlying hypercalcemia, and adrenal insufficiency itself may have contributed to this finding. She had excision of left atrial myxoma and has continued to exhibit normal calcium levels on steroid replacement therapy. Repeat chest CT to further characterize these pulmonary findings is planned. This case illustrates a unique constellation of endocrine features associated with severe hypercalcemia in Carney complex. Presentation: 6/1/2024

Human placental mesenchymal stem cells transplantation repairs the alveolar epithelial barrier to alleviate lipopolysaccharides-induced acute lung injury

Acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) are accompanied by high mortality rates and few effective treatments. Transplantation of human placental mesenchymal stem cells (hPMSCs) may attenuate ALI and the mechanism is still unclear. Our study aimed to elucidate the potential protective effect and therapeutic mechanism of hPMSCs against lipopolysaccharide (LPS)-induced ALI, An ALI model was induced by tracheal instillation of LPS into wild-type (WT) and angiotensin-converting enzyme 2 (ACE2) knockout (KO) male mice, followed by injection of hPMSCs by tail vein. Treatment with hPMSCs improved pulmonary histopathological injury, reduced pulmonary injury scores, decreased leukocyte count and protein levels in bronchoalveolar lavage fluid(BALF), protected the damaged alveolar epithelial barrier, and reversed LPS-induced upregulation of pro-inflammatory factors Interleukin-6 (IL-6) and Tumor necrosis factor-α(TNF-α) and downregulation of anti-inflammatory factor Interleukin-6(IL-10) in BALF. Moreover, administration of hPMSCs inhibited Angiotensin (Ang)II activation and promoted the expression levels of ACE2 and Ang (1–7) in ALI mice. Pathological damage, inflammation levels, and disruption of alveolar epithelial barrier in ALI mice were elevated after the deletion of ACE2 gene, and the Renin angiotensin system (RAS) imbalance was exacerbated. The therapeutic effect of hPMSCs was significantly reduced in ACE2 KO mice. Our findings suggest that ACE2 plays a key role in hPMSCs repairing the alveolar epithelial barrier to protect against ALI, laying a new foundation for the clinical treatment of ALI.

Association of Angiotensin Converting Enzyme (insertion\deletion) and Angiotensin II Type 1 Receptor (A1166C) gene polymorphisms with diabetic nephropathy in Iraqi type 2 diabetic patients

Renin-angiotensin-aldosterone system abnormalities are the most prevalent cause of renal hemodynamic abnormalities, and candidate genes in this system are involved in the etiology of diabetic nephropathy (DN). A polymorphism in the angiotensin converting enzyme (ACE) gene I(insertion)\D(deletion) has been correlated to plasma ACE levels. Furthermore, the Angiotensin II Type 1 Receptor AGT1R (A1166C) expression pattern is highly related to nephropathy. The objectives of this study involved evaluating the frequency of the ACE (I/D) and AGT1R (A1166C) gene polymorphisms and investigating the association of these polymorphism with the development of DN in Iraqi patients with Type 2 diabetes mellitus (T2DM) and evaluating the levels of several urinary and serum markers in relation to studied polymorphisms. This is a cross-sectional study that included 161 T2DM patients whom were divided into two groups: T2DM with DN(included 98 patients) and normalbuminuric T2DM (included 63 patients). ACE gene polymorphism analysis revealed that the D allele was far more prevalent in DN patients compared to normalbuminuric patients (60.2% vs. 50.8%), while the I allele frequency was 39.8% in DN and 49.2% in normoalbuminuric patients. In addition, DN patients carrying the DD genotype had higher serum kidney injury molecule 1 (KIM1), serum cystatin C (CysC), and HbA1C and lower glomerular filtration rate (GFR) compared to ID+II genotypes. For AGT1R (A1166C), both DN and normalbuminuric patients had a comparable high prevalence of the AA genotype, followed by the AC genotype, while the CC genotype had been seen only in 3 patients. In conclusion, among the studied T2DM patients, individuals with DD genotype had higher frequency of DN and had 2-fold risk for DN compared to II genotype which had the lowest risk for DN. Also the current study shows that the A1166C polymorphisms of AGT1R distribution frequency were similar for both study groups with higher frequency for A allele compared to C allele and not associated with risk of DN in Iraqi T2DM Keywords: Angiotensin Converting Enzyme (I\D) gene polymorphism, Angiotensin II Type 1 Receptor (A166C) gene polymorphisms, Cystatin C, Diabetic nephropathy, Kidney injury molecule1.

Evaluation of Angiotensin-Converting Enzyme 2 Expression In Vivo with Novel 68Ga-Labeled Peptides Originated from the Coronavirus Receptor-Binding Domain.

Angiotensin-converting enzyme 2 (ACE2) is not only a key to the renin-angiotensin-aldosterone system and related diseases, but also the main entry point on cell surfaces for certain coronaviruses, including severe acute respiratory syndrome coronavirus (SARS-CoV) and SARS-CoV-2. By analyzing the different key binding sites from the receptor-binding domain (RBD) of SARS-CoV and SARS-CoV-2, nine new ACE2-targeting peptides (A1 to A9) were designed, synthesized and connected with a chelator, 1,4,7-triazacyclononane-N,N',N''-triacetic acid (NOTA). NOTA-A1, NOTA-A2, NOTA-A4, NOTA-A5, and NOTA-A8 were successfully labeled with [68Ga]Ga3+ and were used for biological evaluation. [68Ga]Ga-NOTA-A2, [68Ga]Ga-NOTA-A5, and [68Ga]Ga-NOTA-A8 showed specific binding to ACE2 via cell assays, and their binding sites and binding capacity were calculated by molecular docking and molecular dynamics simulations. In tumor-bearing mice, A549 tumors were visualized 60 min postinjection of [68Ga]Ga-NOTA-A2, [68Ga]Ga-NOTA-A5, or [68Ga]Ga-NOTA-A8. These peptides also accumulated in the organs with high-level ACE2 expression, confirmed by immunohistochemical stain. Among them, [68Ga]Ga-NOTA-A5 exhibited the highest tumor uptake and tumor/background ratio, and it successfully tracked the increased ACE2 levels in mice tissues after excessive Losartan treatment. In a first-in-human study, the distribution of [68Ga]Ga-NOTA-A5 was evaluated with positron emission tomography/computed tomography (PET/CT) in three participants without adverse events. 68Ga-labeled peptides originated from the coronavirus RBD, with [68Ga]Ga-NOTA-A5 as a typical representative, seem to be safe and effective for the evaluation of ACE2 expression in vivo with PET/CT, facilitating further mechanism investigation and clinical evaluation of ACE2-related diseases.

Activation of ACE2/Ang-(1–7)/Mas axis improves cognitive dysfunction induced by isoflurane in mice via inhibiting oxidative stress

BackgroundLong-term inhalation anesthesia is known to be associated with postoperative cognitive dysfunction. Our previous studies have confirmed that oxidative stress damage contributes to its mechanistic connection. Angiotensin-converting enzyme 2 (ACE2)/Angiotensin-(1–7)/Mas axis plays a crucial role in balancing the classic Renin-Angiotensin System (RAS) and regulating oxidative stress. This research aims to investigate the involvement of the ACE2/Angiotensin-(1–7)/Mas axis in the development of cognitive impairment induced by long-term isoflurane anesthesia. Methods3-month-old male C57BL/6 mice were randomly assigned to four groups: Control + Vehicle (C + Veh), Anesthesia + Vehicle (A + Veh), Control + Diminazene aceturate (C + DIZE), and Anesthesia + Diminazene aceturate (A + DIZE). Long-term isoflurane exposure was utilized to induce cognitive impairment. DIZE was administered intraperitoneally to mice 10 days prior to anesthesia to intervene ACE2. Cognitive function was administered using Y-maze and fear conditioning test. Flow Cytometry was used to measure the levels of ROS. Western blot was used to determine the expression levels of ACE2 and Mas, as well as the cognitive proteins such as phosphorylated N-methyl-D-aspartate receptor subtype 2B (p-NR2B) and Brain-Derived Neurotrophic Factor (BDNF). ResultsWe successfully constructed a long-term isoflurane anesthesia-mediated cognitive dysfunction model. Following long-term isoflurane anesthesia, there was a decrease in the levels of ACE2 and Mas in the hippocampus, accompanied by increased oxidative stress and significant cognitive impairment. Treatment with the ACE2 activator DIZE effectively restored the levels of ACE2 and Mas and decreased the content of ROS. Notably, DIZE treatment ameliorated cognitive dysfunction induced by long-term isoflurane exposure. ConclusionsThe findings suggest that the activation of the ACE2/Ang-(1–7)/Mas axis could reduce oxidative stress and improve cognitive impairment. ACE2/Ang-(1–7)/Mas axis may play a prophylactic role in mitigating isoflurane-induced cognitive decline and other cognitive impairments related to oxidative stress.

Abstract P209: The novel angiotensin Alamandine-(1-5) is increased in plasma of pediatric patients with primary nephrotic syndrome

Background and Aim: The Renin Angiotensin System (RAS) has an important role in the pathophysiology of primary nephrotic syndrome (NS). It was previously found that urinary levels of angiotensin converting enzyme 2 (ACE2) are reduced in patients with NS in comparison to health controls. The aim of this study was to measure the novel angiotensin peptide, Alamandine-(1-5), in plasma samples of patients with primary NS and to compare with sex and age-matched controls. Methods: Blood samples of pediatric patients with primary NS (n=11) and of sex and age-matched health controls (n=11) were collected in sterile tubes with 7.5% (w/v) EDTA. After plasma separation and purification by solid phase extraction, the circulating levels of Alamandine and of Alamandine-(1-5) were measured by Mass Spectrometry using multiple reaction monitoring on an ACQUITY I-Class UPLC system coupled to electrospray ionization (ESI) tandem mass spectrometry (LC-ESI-MS/MS Xevo TQ-S). Data were compared between patients and controls and associated with laboratory findings. Continuous variables were presented as mean ± standard error of the mean. Results: A total of 11 patients (7 males) with NS with mean age of 10.65±3.66 were compared to 11 controls (6 males) and with 10.86±4.35 years. In terms of disease response, 5 patients were in partial remission, 5 patients in total remission and only 1 patient was in disease relapse. All patients have normal renal function. Plasma levels of Alamandine-(1-5) were significantly higher in patients when compared to controls (28.03±7.54 vs. 10.68±3.02 pg.mL-1 in controls). Despite a mild decrease in patients, plasma levels of Alamandine did not differ between groups (19.54±6.33 vs 26.09±6.12 pg.mL-1 in controls). No correlations were found between RAS molecules and proteinuria and with the medications in use. However, Alamandine-(1-5) negatively correlated with plasma levels of albumin (r= -0.695; p=0.038). In addition, Alamandine negatively correlated with total cholesterol (r=-0.700; p = 0.036), LDL (r=-0.800; p=0.004), and HDL (r = -0.762; p = 0.038). Conclusion: The novel RAS peptide Alamandine-(1-5) is significantly increased in primary NS and inversely correlated with plasma albumin levels. These findings suggest a potential role of Alamandine-(1-5) in NS

Sivelestat protects against acute lung injury by up-regulating angiotensin-converting enzyme 2/angiotensin-(1-7)/Mas receptors.

Acute lung injury (ALI) and its most severe manifestation of acute respiratory distress syndrome (ARDS) is a disease with a clinical mortality rate of up to 40% and is one of the most dangerous and common complications of severe coronavirus disease 2019 (COVID-19). Sivelestat (SIV) is the only licensed therapeutic medicine in the world for ALI/ARDS treatment. The angiotensin-converting enzyme 2 (ACE2)/angiotensin (Ang)-(1-7)/Mas receptor axis is critical in the prevention of ALI/ARDS. This study aims to investigate whether SIV alleviates lipopolysaccharides (LPS)-induced ALI by inhibiting the down-regulation of ACE2/Ang-(1-7)/Mas receptor axis expression. In vivo, 90 male Sprague-Dawley rats were randomized into 5 groups. Then, we pretreated different groups of rats with dexamethasone (DEX) or SIV. Rats were sacrificed at three different time points (3, 6, and 12 hours) following LPS instillation. In vitro, RAW264.7 cells were divided into 11 groups. Different groups of cells were pretreated with DEX or SIV. And then added with LPS for 3, 6, and 12 hours. Next, we introduced A779, a potent Ang-(1-7) receptor antagonist, and DX600 as the ACE2 antagonist in different groups. Then the protein and messenger RNA (mRNA) expression levels of ACE2 in rat lung tissue and the expression levels of tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6) and Ang-(1-7) in the rat serum and the cell culture supernatant were measured. And the data were statistically analyzed. In vivo, the rats pretreated with SIV or DEX had significantly lower lung wet/dry (W/D) ratios and lung pathological alterations than those exposed to LPS only. Both in vivo and in vitro, we observed that SIV or DEX significantly attenuated the LPS-induced up-regulation of IL-6 and TNF-α levels, and the down-regulation of ACE2 and Ang-(1-7) levels. In vitro, the pretreatment of the RAW264.7 cells with DX600 and A779 significantly reduced and even abolished the protective effects of SIV. Therefore, it was concluded that SIV protected against LPS-induced ALI and decreased inflammatory cytokine release by up-regulating the ACE2/Ang-(1-7)/Mas receptor axis. Our results enrich the theoretical foundation for the clinical application of SIV and provide fresh ideas for the treatment of ALI/ARDS.

Abstract 73: Extracellular vesicles-derived miR-125b-5p/miR-125a-5p promotes hypertension by regulating angiotensin-converting enzyme 2

Therapeutic targeting of non-coding RNAs, particularly microRNA (miRNA), presents an appealing approach in the treatment of chronic diseases such as resistant hypertension. Recently, miRNA have emerged as promising targets for therapeutic intervention, capable of regulating critical genes to provide a suitable solution to the lack of efficacy of current treatments. Our comprehensive miRNA profiling of plasma extracellular vesicles (EV) from DOCA-salt hypertensive mice of both sexes, compared to sham controls, identified two miRNA implicated in salt-sensitive hypertension, namely miR-125b-5p and miR-125a-5p. Our bioinformatic analysis suggests that these miRNA could be involved in angiotensin-converting enzyme 2 (ACE2) downregulation in hypertension. The present study intended to validate ACE2 as a target of miR-125. Quantitative RT-PCR and capillary western analysis of hypothalami from C57BL/6J DOCA+Salt hypertensive male and female mice following 3-weeks of DOCA+Salt treatment (n=5-6 per group, 3-month old), detected a significant decrease in ACE2 mRNA (males: 0.34±0.03 vs. 1.02±0.02; females: 0.65±0.08 vs. 1.01±0.01; P&lt;0.05) and protein (males: 0.17±0.02 vs. 0.31±0.05; females: 0.16±0.03 vs. 0.37±0.07; P&lt;0.05) expression for both sexes. Further investigation in bEND.3 cells treated with different concentrations of Ang-II (0, 10, 100 nM) for 12, 24, and 48 hours, demonstrated a dose-dependent negative correlation between miR-125b-5p (r≈-0.9978) or miR-125a-5p (r≈-1.002) and ACE2 gene expression, independently of time. When treated with miR-125 mimics the cells demonstrated a consistent downregulation of ACE2 protein levels (miR-125b-5p: 0.6±0.1 and miR-125a-5p: 2.0±0.2 vs. control: 2.8±0.3). Conversely, no significant change in ACE2 protein levels was observed with the respective miRNA inhibitors. Using a firefly/Renilla luciferase assay, we further identified ACE2 as a validated primary target for these miRNA. While miR-125b-5p indirectly modulates the expression of the Ace2 gene by targeting important transcription factors like Sp1 and STAT3, our data further elucidate that miR-125b-5p and/or miR-125a-5p directly reduce ACE2 levels by targeting ACE2 3’UTR mRNA. Additional work is warranted to investigate these specific regulatory mechanisms based on cell specificity, physiological conditions, and sex differences.

O48 CHRONIC EXPOSURE TO POLLUTED URBAN AIR ALTERS MOUSE SYSTEMIC AND TISSUE-SPECIFIC COMPONENTS OF THE RENIN-ANGIOTENSIN SYSTEM (RAS)

Background and Objective: Chronic exposure to air pollution induces pulmonary, cardiovascular, and renal diseases. In the current study, we investigated the hypothesis that postulates that a dysregulation of the RAS may contribute to these pathologies. Methods: Male Balb/C mice were exposed to urban air from Buenos Aires City, in whole-body exposure chambers for 14 weeks. Control animals were exposed to filtered air. The levels of main RAS components including angiotensin-converting enzyme (ACE) and ACE2; AT1, AT2, and Mas receptors (R) were determined in mouse lungs, kidneys, and heart, through western blotting (WB) and RT-qPCR, respectively. The tissue content of cytokine mARN was determined by RT-qPCR. The tissue content of nitrotyrosine and 4-hydroxynonenal (4-HNE) levels, were determined by WB. Circulating angiotensin (Ang) II levels were determined by radioimmunoassay. Systolic blood pressure was measured by the tail-cuff method. Results: Exposure to air pollution resulted in a) Increased levels of ACE and AT1R mRNA in the lungs and augmented the abundance markers of inflammation (TNF-α, IL-6, and IL-1β) and oxidative stress (nitrotyrosine and 4-HNE) in this tissue, b) increased levels of MasR mRNA (all analyzed tissues) and MasR protein levels (lungs and heart), c) upregulated mRNA and protein abundance of cardiac and renal AT2Rs, and d) Increased levels of circulating Ang II and e) augmented systolic blood pressure. Conclusions: Our findings indicate that chronic exposure to air pollution alters the expression of both tissue and systemic components of the RAS. Since both AT2R and MasRs have been shown to participate in tissue-repair mechanisms, the upregulation of these receptors detected in mouse lungs, heart, and kidney after chronic exposure to polluted urban air could represent a mechanism of tissue protection against damage induced by air pollution.

Antihypertensive and antioxidant effects of food-derived bioactive peptides in spontaneously hypertensive rats.

Hypertension significantly impacts the survival and quality of life of animals, often leading to chronic kidney failure. Current clinical drugs used to manage hypertension carry the risk of causing adverse reactions. In contrast, certain natural peptides have demonstrated the ability to safely reduce blood pressure by inhibiting the production of angiotensin. We administered four biologically active peptide solutions to spontaneously hypertensive rats: derived from corn, wheat, egg white, and soybean. The efficacy of these peptides in reducing blood pressure was assessed through regular measurements of systolic pressure. Additionally, we analyzed levels of angiotensin-converting enzyme and angiotensin 2 using immunohistochemistry and ELISA invivo. The indicators of oxidative stress and inflammation in hypertensive rats were evaluated using qRT-PCR and ELISA, respectively. Both wheat (from 182.5 ± 12.26 mmHg at day 0 to 168.86 ± 5.86 mmHg at day 20, p = .0435) and soybean (from 189 ± 2.19 mmHg at day 0 to 178.25 ± 5.14 mmHg at day 20, p = .0017) notably lowered systolic blood pressure compared to their starting systolic blood pressures in spontaneously hypertensive rats. Both wheat and soybean peptides significantly reduced plasma ANG II levels, akin to captopril's effect. Wheat peptides additionally exhibited antioxidant properties. Only the corn peptide showed a significant increase in transcript levels of the proinflammatory factors IL-6 and TNF-α. At the protein level, all four kinds of peptides significantly elevated IL-6 levels while inhibiting TNF-α secretion. This study demonstrates that wheat peptides and soybean peptides administered as dietary supplements exhibit significant hypotensive and antioxidant effects.

Biochemical Risk Factors of Atherosclerosis in Patients with Severe and Non-severe COVID-19

Background: COVID-19 may trigger the progression of atherosclerosis, potentially leading to its clinical manifestation. Among the serum biomarkers related to atherosclerotic disease, it seems helpful to evaluate biochemical factors such as CD147, ACE2, and ACE in patients with COVID-19. Methods: In this case-control study, serum samples from 90 patients were analyzed. The cohort included 30 patients hospitalized in the intensive care unit with COVID-19, 30 patients hospitalized in the ward with COVID-19, and 30 healthy individuals from Ayatollah Kashani Hospital (Tehran, Iran). These patients were admitted between December 10, 2022, and March 10, 2023. The concentrations of cholesterol, triglycerides, high-density lipoprotein (HDL), low-density lipoprotein (LDL), and the activity levels of angiotensin-converting enzyme (ACE), angiotensin-converting enzyme 2 (ACE2), troponin, CPK, CPK-MB, and CD147 were determined and analyzed among the three groups. Results: There was no significant difference in age between the patients (55.40 ± 10.34 years) and the control group (58.34 ± 11.71 years). SARS-CoV2 viral RNA was detected in the pharyngeal swab samples of the COVID-19 patients. The levels of CD-147 (2528.43 ± 12.43 vs. 2176.7 ± 9.87 vs. 1346.3 ± 14.23), ACE (83 ± 3.05 vs. 97 ± 1.55 vs. 30.1 ± 2.32), troponin (0.972 ± 0.25 vs. 0.784 ± 0.21 vs. 0.021 ± 0.68), and cholesterol (199.73 ± 2.43 vs. 175.87 ± 5.21 vs. 144.97 ± 8.74) were significantly higher in severe cases compared to non-severe cases (P &lt; 0.05). ACE (AUC = 0.894) and CD147 (AUC = 0.821) had the highest sensitivity and specificity among the studied factors, respectively. Patients with normal levels of ACE and CPK-MB had a 0.16 times lower and 4.37 times greater chance of experiencing severe disease, respectively. Three strong correlations were found among the studied parameters: CD147 with ACE2 (r = 0.721) and cholesterol with triglyceride (r = 0.602) (P &lt; 0.05). Conclusions: Examining ACE and CD147 can help determine a person's susceptibility to atherosclerosis. These two factors have greater sensitivity and specificity and could be used as potential markers for monitoring disease progression.

Mathematical Modeling of Impacts of Patient Differences on Renin-Angiotensin System and Applications to COVID-19 Lung Fibrosis Outcomes.

Patient-specific premorbidity, age, and sex are significant heterogeneous factors that influence the severe manifestation of lung diseases, including COVID-19 fibrosis. The renin-angiotensin system (RAS) plays a prominent role in regulating the effects of these factors. Recent evidence suggests patient-specific alteration of RAS homeostasis concentrations with premorbidity and the expression level of angiotensin converting enzyme 2 (ACE2) during COVID-19. However, conflicting evidence suggests decreases, increases, or no changes in RAS after SARS-CoV-2 infection. In addition, detailed mechanisms connecting the patient-specific conditions before infection to infection-induced RAS alteration are still unknown. Here, a multiscale model is developed to quantify the systemic contribution of heterogeneous factors of RAS during COVID-19. Three submodels are connected-an ABM COVID-19 in-host lung tissue model, a RAS model, and a fibrosis model to investigate the effects of patient-group-specific factors in the systemic alteration of RAS and collagen deposition in the lung. The model results indicate cell death due to inflammatory response as a major contributor to the reduction of ACE and ACE2. In contrast, there are no significant changes in ACE2 dynamics due to viral-bound internalization of ACE2. Reduction of ACE and ACE2 downregulates the homeostasis concentration of RAS, including angiotensin II (ANGII), in the lung tissue. At the same time, the decrease in ACE2 increases systemic ANGII and results in severe lung injury and fibrosis. The model explains possible mechanisms for conflicting evidence of RAS alterations in previously published studies, and simulated results are consistent with reported RAS peptide values for SARS-CoV-2-negative and SARS-CoV-2-positive patients. We observed decreased RAS peptides for all virtual patient groups with aging in both sexes. In contrast, large variations in the magnitude of reduction were observed between male and female virtual patients in the older and middle-aged groups. We also predicted that feedback of ANGII·AT1R to renin could restore ANGI homeostasis concentration but fails to restore homeostasis values of RAS peptides downstream of ANGI. In addition, the results show that ACE2 variations with age and sex significantly alter the concentrations of RAS peptides and lead to collagen deposition with slight variations depending on age and sex. This model may find further applications in patient-specific calibrations of tissue models for acute and chronic lung diseases to develop personalized treatments.

Diets containing phytobiotics, l-arginine, vitamin E and captopril modulate ascites syndrome-related genes expression in broiler chickens exposed to low ambient temperature.

Our hypothesis centred on the potential to mitigate ascites outbreaks in birds exposed to cold stress by inhibiting pulmonary artery contraction through dietary intervention. This study aimed to evaluate the effect of natural and synthetic medications on growth performance, ascites-related parameters and the expression of ascites-related genes in the lung tissue of broiler chickens under low ambient temperature. We randomly assigned 450 one-day-old male Ross 308 chicks to six dietary treatments across five replicate pens, each containing 15 chicks. The treatments included a basal diet (control), and the basal diet was supplemented with hydroalcoholic extracts of sumac (HES, 200mg/kg), Syrian mesquite (HEM, 200mg/kg), l-arginine (40% above requirement), captopril (15mg/kg) and vitamin E (100mg/kg). Diets containing HEM, l-arginine and vitamin E resulted in increased average daily gain on days 8-14 and 0-28, whereas HES showed a similar effect only during days 8-14 compared to the control diet (p<0.05). Additionally, feed additives decreased packed cell volume, left and right ventricle volumes and systolic blood pressure (p<0.05). Moreover, chickens fed the control and l-arginine diets exhibited higher levels of angiotensin converting enzyme (ACE) mRNA in lung tissue compared to those fed HES, HEM and captopril (p<0.05). Meanwhile, supplementation with HEM and l-arginine increased the expression of inducible nitric oxide synthase (iNOS) mRNA in lung tissue compared to other treatments (p<0.05). Regarding Cu/Zn-superoxide dismutase (Cu/Zn-SOD) expression, feed additives increased mRNA level in lung tissue, except for captopril (p<0.05). This study demonstrates that the plant extracts may reduce the incidence of ascites syndrome not only through their antioxidant properties but also by modulating the expression of ACE, iNOS and Cu/Zn-SOD genes.

Epigenetic Regulation of the Renin-Angiotensin-Aldosterone System in Hypertension.

Activation of the renin-angiotensin-aldosterone system (RAAS) plays an important pathophysiological role in hypertension. Increased mRNA levels of the angiotensinogen angiotensin-converting enzyme, angiotensin type 1 receptor gene, Agtr1a, and the aldosterone synthase gene, CYP11B2, have been reported in the heart, blood vessels, and kidneys in salt-sensitive hypertension. However, the mechanism of gene regulation in each component of the RAAS in cardiovascular and renal tissues is unclear. Epigenetic mechanisms, which are important for regulating gene expression, include DNA methylation, histone post-translational modifications, and microRNA (miRNA) regulation. A close association exists between low DNA methylation at CEBP-binding sites and increased AGT expression in visceral adipose tissue and the heart of salt-sensitive hypertensive rats. Several miRNAs influence AGT expression and are associated with cardiovascular diseases. Expression of both ACE and ACE2 genes is regulated by DNA methylation, histone modifications, and miRNAs. Expression of both angiotensinogen and CYP11B2 is reversibly regulated by epigenetic modifications and is related to salt-sensitive hypertension. The mineralocorticoid receptor (MR) exists in cardiovascular and renal tissues, in which many miRNAs influence expression and contribute to the pathogenesis of hypertension. Expression of the 11beta-hydroxysteroid dehydrogenase type 2 (HSD11B2) gene is also regulated by methylation and miRNAs. Epigenetic regulation of renal and vascular HSD11B2 is an important pathogenetic mechanism for salt-sensitive hypertension.