The vasoprotective axes of the renin-angiotensin system: Physiological relevance and therapeutic implications in cardiovascular, hypertensive and kidney diseases

The prevalence of monotherapy and combination therapy in hypertension in China from 2019 to 2021: A nationwide population-based cross-sectional study

There are no nationwide surveys on antihypertensive drugs in China. In order to assess the current status of antihypertensive drug therapy in patients with hypertension and analyzed factors that may affect combination therapy, using convenience sampling, we recruited 305,624 patients with hypertension from the Chinese Cardiovascular Association Database-Hypertension Center between January 2019 and December 2021. Chi-squared test was performed to analyze the administered antihypertensive drug types and their combinations in different hospital settings. Logistic regression was used to assess the factors influencing combination therapy. We found around 33.1% of the participants had stage 2 and above hypertension, of which 67.9% were treated with combination therapy. In community or general hospitals, the most common monotherapy was calcium channel blockers (CCB), angiotensin-converting enzyme inhibitor/angiotensin II receptor inhibitor (ACEI/ARB) and diuretic were the main single-pill combinations (SPCs), and ACEI/ARB and CCB were the main free combination. From 2019 to 2021, the rates of combination therapy increased (58.8%-64.1%) with SPCs from 25.9% to 31.0% and free combination from 31.9% to 32.6%. Patients aged < 60 years, with stage 2 and above hypertension, with an education level of high school and above, visiting general hospitals, living in the eastern region of China, with hypertension risk factors and comorbidities, and without anxiety or depression were more likely to receive combination therapy (all P < .05). The combination therapy use rate increased yearly and the rate of SPCs rose obviously. Individual, hospital, and regional differences in patients with hypertension influenced combination therapy.

The Evaluation of Drugs as Potential Modulators of the Trafficking and Maturation of ACE2, the SARS-CoV-2 Receptor

ACE2, part of the angiotensin-converting enzyme family and the renin-angiotensin-aldosterone system (RAAS), plays vital roles in cardiovascular and renal functions. It is also the primary receptor for SARS-CoV-2, enabling its entry into cells. This project aimed to study ACE2's cellular trafficking and maturation to the cell surface and assess the impact of various drugs and compounds on these processes. We used cellular and biochemical analyses to evaluate these compounds as potential leads for COVID-19 therapeutics. Our screening assay focused on ACE2 maturation levels and subcellular localization with and without drug treatments. Results showed that ACE2 maturation is generally fast and robust, with certain drugs having a mild impact. Out of twenty-three tested compounds, eight significantly reduced ACE2 maturation levels, and three caused approximately 20% decreases. Screening trafficking inhibitors revealed significant effects from most molecular modulators of protein trafficking, mild effects from most proposed COVID-19 drugs, and no effects from statins. This study noted that manipulating ACE2 levels could be beneficial or harmful, depending on the context. Thus, using this approach to uncover leads for COVID-19 therapeutics requires a thorough understanding ACE2's biogenesis and biology.

Determinants of Systemic SARS-CoV-2-Specific Antibody Responses to Infection and to Vaccination: A Secondary Analysis of Randomised Controlled Trial Data

SARS-CoV-2 infections elicit antibodies against the viral spike (S) and nucleocapsid (N) proteins; COVID-19 vaccines against the S-protein only. The BCG-Corona trial, initiated in March 2020 in SARS-CoV-2-naïve Dutch healthcare workers, captured several epidemic peaks and the introduction of COVID-19 vaccines during the one-year follow-up. We assessed determinants of systemic anti-S1 and anti-N immunoglobulin type G (IgG) responses using trial data. Participants were randomised to BCG or placebo vaccination, reported daily symptoms, SARS-CoV-2 test results, and COVID-19 vaccinations, and donated blood for SARS-CoV-2 serology at two time points. In the 970 participants, anti-S1 geometric mean antibody concentrations (GMCs) were much higher than anti-N GMCs. Anti-S1 GMCs significantly increased with increasing number of immune events (SARS-CoV-2 infection or COVID-19 vaccination): 104.7 international units (IU)/mL, 955.0 IU/mL, and 2290.9 IU/mL for one, two, and three immune events, respectively (p < 0.001). In adjusted multivariable linear regression models, anti-S1 and anti-N log10 concentrations were significantly associated with infection severity, and anti-S1 log10 concentration with COVID-19 vaccine type/dose. In univariable models, anti-N log10 concentration was also significantly associated with acute infection duration, and severity and duration of individual symptoms. Antibody concentrations were not associated with long COVID or long-term loss of smell/taste.

Mitochondrial KATP channel-mediated autophagy contributes to angiotensin II-induced vascular dysfunction in mice

BACKGROUND AND AIM

The present study aimed to investigate whether the mitochondrial KATP channel contributes to angiotensin II (Ang II)-induced vascular dysfunction, the development of hypertension, and atherosclerosis.

METHODS AND RESULTS

ApoE (-/-) mice fed a high-fat diet were chronically infused with Ang II for eight weeks and concomitantly treated with losartan (ARB), apocynin, or 5-hydroxy decanoate (5-HD), or 3-methyladenine (3-MA). Systolic blood pressure was measured, and pathological changes of aortic or liver tissue were observed. Nitric oxide (NO), superoxide dismutase 2 (SOD2) levels and vasorelaxation rate were measured, and protein and mRNA expressions were examined by western blot and RT-PCR. Ang II-induced development of hypertension was suppressed not only by ARB, and apocynin but also by 5-HD or 3-MA. Ang II infusion decreased aortic NO production and relaxation, as well as SOD2 activity in liver, which were improved by all treatments. In addition, Ang II-induced activation of autophagy was suppressed by 5-HD in aortic tissue, furthermore, Ang II increases the atherosclerotic index in plasma and exacerbates the development of atherosclerosis by increases of fat deposition in the aorta and liver. Lipid metabolism-related mRNA expressions (LXR-α, LDLR, SRBI, Acca, and FASN) were changed by Ang II. Similarly, not only ARB, and apocynin, but also 5-HD and 3-MA suppressed Ang II-induced these changes.

CONCLUSIONS

Our present findings evidence that mitochondrial KATP channel-mediated autophagy contributes to Ang II-induced vascular dysfunction, development of hypertension, and atherosclerosis.

Apelin-13: a novel approach to suppressing renin production in RVHT

Renovascular hypertension (RVHT) is characterized by renal artery stenosis and overactivated renin-angiotensin system (RAS). Apelin, known for its negative modulation of RAS, has protective effects against cardiovascular diseases. The role and mechanisms of the primary active form of apelin, apelin-13, in RVHT are unclear. In this study, male Sprague-Dawley rats were divided into control, two-kidney one-clip (2K1C) model, and 2K1C with apelin-13 treatment groups. Renin expression was analyzed using immunohistochemistry and molecular techniques. Full-length (pro)renin receptor (fPRR) and soluble PRR (sPRR) levels were assessed via Western blotting, and cAMP levels were measured using ELISA. Plasma renin content, plasma renin activity (PRA), angiotensin II (ANG II), and sPRR levels were determined by ELISA. Human Calu-6 and mouse As4.1 cells were used to investigate renin production mechanisms. The 2K1C model exhibited increased systolic blood pressure, plasma renin content, PRA, sPRR, and ANG II levels, while apelin-13 treatment reduced these elevations. Apelin-13 inhibited cAMP production, renin mRNA expression, protein synthesis, and PRR/sPRR protein expression in renal tissue. In Calu-6 cells, cAMP-induced fPRR and site-1 protease (S1P)-derived sPRR expression, which was blocked by cAMP-responsive element-binding protein (CREB) inhibition. Apelin-13 suppressed cAMP elevation, CREB phosphorylation, fPRR/sPRR protein expression, and renin production. Recombinant sPRR (sPRR-His) stimulated renin production, which was inhibited by the PRR decoy peptide PRO20 and S1P inhibitor PF429242. These findings suggest that apelin-13 inhibits plasma renin expression through the cAMP/PKA/sPRR pathway, providing a potential therapeutic approach for RVHT. Understanding the regulation of renin production is crucial for developing effective treatments.NEW & NOTEWORTHY Our research elucidated that apelin-13 inhibits renin production through the cAMP/PKA/soluble (pro)renin receptor pathway, presenting a promising therapeutic approach for renovascular hypertension (RVHT) by targeting renin expression mechanisms. These findings underscore the potential of apelin-13 as a novel strategy to address RVHT.

Angiotensin-converting enzyme 2 and AMPK/mTOR pathway in the treatment of liver fibrosis: Should we consider further implications?

This editorial contains comments on the article by Zhao et al in print in the World Journal of Gastroenterology. The mechanisms responsible for hepatic fibrosis are also involved in cancerogenesis. Here, we recapitulated the complexity of the renin-angiotensin system, discussed the role of hepatic stellate cell (HSC) autophagy in liver fibrogenesis, and analyzed the possible implications in the development of hepatocarcinoma (HCC). Angiotensin-converting enzyme inhibitors and angiotensin receptor blockers definitively contribute to reducing hepatic fibrogenesis, whereas their involvement in HCC is more evident in experimental conditions than in human studies. Angiotensin-converting enzyme 2 (ACE2), and its product Angiotensin (Ang) 1-7, not only regulate HSC autophagy and liver fibrosis, but they also represent potential targets for unexplored applications in the field of HCC. Finally, ACE2 overexpression inhibits HSC autophagy through the AMP-activated protein kinase (AMPK)/mammalian target of rapamycin (mTOR) pathway. In this case, Ang 1-7 acts binding to the MasR, and its agonists could modulate this pathway. However, since AMPK utilizes different targets to suppress the mTOR downstream complex mTOR complex 1 effectively, we still need to unravel the entire pathway to identify other potential targets for the therapy of fibrosis and liver cancer.

Chronic Intermittent Hypobaric Hypoxia Reduces Hypothalamic N-Methyl-d-Aspartate Receptor Activity and Sympathetic Outflow in Spontaneously Hypertensive Rats

Guo, Xinqi, Hongyu Ma, Ziye Cui, Qiyue Zhao, Ying Zhang, Lu Jia, Liping Zhang, Hui Guo, Xiangjian Zhang, Yi Zhang, Yue Guan, and Huijie Ma. Chronic intermittent hypobaric hypoxia reduces hypothalamic N-Methyl-d-Aspartate Receptor activity and sympathetic outflow in spontaneously hypertensive rats. High Alt Med Biol. 25:77-88, 2024. Objective: This study aims to determine the role of hypothalamic renin-angiotensin system (RAS) in the antihypertensive effect of chronic intermittent hypobaric hypoxia (CIHH). Methods: Wistar-Kyoto (WKY) rats and spontaneously hypertensive rats (SHRs) received 35 days of hypobaric hypoxia simulating an altitude of 4,000 m, 5 h/day. The levels of RAS, blood pressure, and N-methyl-d-aspartate receptor (NMDAR) activities of hypothalamic paraventricular nucleus (PVN) presympathetic neurons from each group of rats were determined. Results: The systolic blood pressure, diastolic blood pressure, and mean arterial blood pressure (MAP) of SHRs significantly decreased from the third week of CIHH treatment. This blood pressure reduction effect could be maintained for at least 2 weeks after stopping the CIHH treatment. CIHH treatment also attenuated the decrease in MAP and renal sympathetic nerve activity induced by hexamethonium administration in SHRs, but not in WKY rats. Furthermore, CIHH reversed the increase in serum angiotensin (Ang)II concentration and the expression of PVN angiotensin-converting enzyme (ACE) and AngII type 1 (AT1) receptors, as well as the decrease in serum Ang1-7 concentration and the expression of PVN ACE2 and Mas receptors in SHRs. In addition, the administration of CIHH resulted in a reduction in the frequency of miniature excitatory postsynaptic currents and amplitude of NMDAR current in PVN presympathetic neurons of SHRs, which means that CIHH decreased the pre- and postsynaptic NMDAR activity of PVN presympathetic neurons in SHRs. However, pretreatment with A779 (a Mas receptor blocker) or AngII abrogated the above effects. Meanwhile, Ang1-7 pretreatment mimicked the CIHH effect on pre- and postsynaptic NMDAR activity of presympathetic neurons in SHRs. Conclusions: Our data indicate that CIHH reduces pre- and postsynaptic NMDAR activity of PVN presympathetic neurons, sympathetic outflow, and blood pressure by decreasing the activity of the ACE/AngII/AT1 axis and increasing the activity of ACE2/Ang1-7/Mas axis in the hypothalamus in hypertension.

Nitric oxide-cyclic GMP role in Ang II induced hyperpolarization in bovine aortic endothelium cell line (BAE-1)

Angiotensin II (Ang II), a mitogen-activated peptide, exerts numerous effects on the cardiovascular system including the regulation of blood pressure. The current study focused on the potential mechanisms that seem to be involved in Ang II vasodilation using bovine aortic endothelial cells (BAE-1) cell lines. Expression of the Ang II receptor (AT2) in BAE-1 was checked by western blots in the presence of valsartan (AT1 inhibitor). To check if Ang II's vasodilator impact was mediated by the nitric oxide (NO) pathway, the Griess reagent was used. Furthermore, cell-attached patch-clamp and fire-polished borosilicate electrodes with a resistance of 3-5 MΩ in the working solutions was used to record membrane currents from treated BAE-1. BEA-1 revealed 50 kDa immunoreactive bands that matched AT2. The concentration of AT2 was elevated in valsartan-treated cells in comparison to control cells. The biochemical experimental data indicated that the NO level increased in a concentration-dependent manner. Meanwhile, Ang II at a concentration of 1 µM, the level of NO increased more than at 100 µM. In patch-clamp experiments, K current and chord conductance were enhanced after incubation of Ang II with valsartan. When 100 µM Ang II was added, the current peaked rapidly and after 15 min of incubation, the maximum value was obtained, as opposed to 10 min and control (110.9 ± 13.3 pA control, 141.4 ± 30.4 pA after 10 min and 174.4 ± 49.3 pA after 15 min). Ang II type two receptor inhibitor (PD1231777) reduced the current and conductance induced by Ang II. The presented data revealed that Ang II released NO via the activation of AT2. K currents were stimulated by Ang II and evoked mainly a current consistent with the activation of K channels.

Novel Insights into the Cardioprotective Effects of the Peptides of the Counter-Regulatory Renin-Angiotensin System

Currently, cardiovascular diseases are a major contributor to morbidity and mortality worldwide, having a significant negative impact on both the economy and public health. The renin-angiotensin system contributes to a high spectrum of cardiovascular disorders and is essential for maintaining normal cardiovascular homeostasis. Overactivation of the classical renin-angiotensin system is one of the most important pathophysiological mechanisms in the progression of cardiovascular diseases. The counter-regulatory renin-angiotensin system is an alternate pathway which favors the synthesis of different peptides, including Angiotensin-(1-7), Angiotensin-(1-9), and Alamandine. These peptides, via the angiotensin type 2 receptor (AT2R), MasR, and MrgD, initiate multiple downstream signaling pathways that culminate in the activation of various cardioprotective mechanisms, such as decreased cardiac fibrosis, decreased myocardial hypertrophy, vasodilation, decreased blood pressure, natriuresis, and nitric oxide synthesis. These cardioprotective effects position them as therapeutic alternatives for reducing the progression of cardiovascular diseases. This review aims to show the latest findings on the cardioprotective effects of the main peptides of the counter-regulatory renin-angiotensin system.

Impact of ACE I gene insertion/deletion, A-240T polymorphisms and the renin-angiotensin-aldosterone system on COVID-19 disease

BACKGROUND

The coronavirus disease 2019 (COVID-19) pandemic is driven by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, which has led to an enormous burden on patient morbidity and mortality. The renin-angiotensin-aldosterone system (RAAS) plays a significant role in various pulmonary diseases. Since SARS-CoV-2 utilizes the angiotensin-converting enzyme (ACE)2 receptor to exert its virulence and pathogenicity, the RAAS is of particular importance in COVID 19.

METHODS

Our preliminary study investigates retrospectively the influence of selected ACE-polymorphisms (I/D location at intron 16 in the B-coding sequence (rs4646994) and A-240T (rs 4291) at the A-promoter) as well as ACE1 and ACE2 serum levels on disease severity and the inflammatory response in inpatients and outpatients with COVID-19.

RESULTS

Our study included 96 outpatients and 88 inpatients (65.9% male, mean age 60 years) with COVID-19 from April to December 2020 in four locations in Germany. Of the hospitalized patients, 88.6% participants were moderately ill (n = 78, 64% male, median age 60 years), and 11.4% participants were severely ill or deceased (n = 10, 90% male, median age 71 years). We found no polymorphism-related difference in disease, in age distribution, time to hospitalization and time of hospitalization for the inpatient group. ACE1 serum levels were significantly increased in the DD compared to the II polymorphism and in the TT compared to the AA polymorphism. There was no significant difference in ACE 1 serum levels l between moderately ill and severely ill patients. However, participants requiring oxygen supplementation had significantly elevated ACE1 levels compared to participants not requiring oxygen, with no difference in ACE2 levels whereas females had significantly higher ACE2 levels.

CONCLUSIONS

Although there were no differences in the distribution of ACE polymorphisms in disease severity, we found increased proinflammatory regulation of the RAAS in patients with oxygen demand and increased serum ACE2 levels in women, indicating a possible enhanced anti-inflammatory immune response.

CLINICAL TRIAL REGISTRATION

PreBiSeCov: German Clinical Trials Register, DRKS-ID: DRKS00021591, Registered on 27th April 2020.

Multi-omics Investigations in Endocrine Systems and Their Clinical Implications

Innovative techniques such as the "omics" can be a powerful tool for the understanding of intracellular pathways involved in homeostasis maintenance and identification of new potential therapeutic targets against endocrine-metabolic disorders. Over the last decades, proteomics has been extensively applied in the study of a wide variety of human diseases, including those involving the endocrine system. Among the most endocrine-related disorders investigated by proteomics in humans are diabetes mellitus and thyroid, pituitary, and reproductive system disorders. In diabetes, proteins implicated in insulin signaling, glucose metabolism, and β-cell activity have been investigated. In thyroid diseases, protein expression alterations were described in thyroid malignancies and autoimmune thyroid illnesses. Additionally, proteomics has been used to investigate the variations in protein expression in adrenal cancers and conditions, including Cushing's syndrome and Addison's disease. Pituitary tumors and disorders including acromegaly and hypopituitarism have been studied using proteomics to examine changes in protein expression. Reproductive problems such as polycystic ovarian syndrome and endometriosis are two examples of conditions where alterations in protein expression have been studied using proteomics. Proteomics has, in general, shed light on the molecular underpinnings of many endocrine-related illnesses and revealed promising biomarkers for both their detection and treatment. The capacity of proteomics to thoroughly and objectively examine complex protein mixtures is one of its main benefits. Mass spectrometry (MS) is a widely used method that identifies and measures proteins based on their mass-to-charge ratio and their fragmentation pattern. MS can perform the separation of proteins according to their physicochemical characteristics, such as hydrophobicity, charge, and size, in combination with liquid chromatography. Other proteomics techniques include protein arrays, which enable the simultaneous identification of several proteins in a single assay, and two-dimensional gel electrophoresis (2D-DIGE), which divides proteins depending on their isoelectric point and molecular weight. This chapter aims to summarize the most relevant proteomics data from targeted tissues, as well as the daily rhythmic variation of relevant biomarkers in both physiological and pathophysiological conditions within the involved endocrine system, especially because the actual modern lifestyle constantly imposes a chronic unentrained condition, which virtually affects all the circadian clock systems within human's body, being also correlated with innumerous endocrine-metabolic diseases.

Sex differences in blood pressure regulation and hypertension: renal, hemodynamic, and hormonal mechanisms

The teleology of sex differences has been argued since at least as early as Aristotle's controversial Generation of Animals more than 300 years BC, which reflects the sex bias of the time to contemporary readers. Although the question "why are the sexes different" remains a topic of debate in the present day in metaphysics, the recent emphasis on sex comparison in research studies has led to the question "how are the sexes different" being addressed in health science through numerous observational studies in both health and disease susceptibility, including blood pressure regulation and hypertension. These efforts have resulted in better understanding of differences in males and females at the molecular level that partially explain their differences in vascular function and renal sodium handling and hence blood pressure and the consequential cardiovascular and kidney disease risks in hypertension. This review focuses on clinical studies comparing differences between men and women in blood pressure over the life span and response to dietary sodium and highlights experimental models investigating sexual dimorphism in the renin-angiotensin-aldosterone, vascular, sympathetic nervous, and immune systems, endothelin, the major renal sodium transporters/exchangers/channels, and the impact of sex hormones on these systems in blood pressure homeostasis. Understanding the mechanisms governing sex differences in blood pressure regulation could guide novel therapeutic approaches in a sex-specific manner to lower cardiovascular risks in hypertension and advance personalized medicine.

Impact of Anti-angiogenic Drugs on Severity of COVID-19 in Patients with Non-Small Cell Lung Cancer

Introduction: The 2019 coronavirus disease (COVID-19) pandemic has reshaped oncology practice, but the impact of anti-angiogenic drugs on the severity of COVID-19 in patients with non-small cell lung cancer (NSCLC) remains unclear. Patients and Methods: We carried out a retrospective study involving 166 consecutive patients with NSCLC who were positive for COVID-19, aiming to determine the effects of anti-angiogenic drugs on disease severity, as defined by severe/critical symptoms, intensive care unit (ICU) admission/intubation, and mortality outcomes. Risk factors were identified using univariate and multivariate logistic regression models. Results: Of the participants, 73 had been administered anti-angiogenic drugs (termed the anti-angiogenic therapy (AT) group), while 93 had not (non-AT group). Comparative analyses showed no significant disparity in the rates of severe/critical symptoms (21.9% vs 35.5%, P = 0.057), ICU admission/intubation (6.8% vs 7.5%, P = 0.867), or death (11.0% vs 9.7%, P = 0.787) between these two groups. However, elevated risk factors for worse outcomes included age ≥ 60 (odds ratio (OR): 2.52, 95% confidence interval (CI): 1.07-5.92), Eastern Cooperative Oncology Group performance status of 2 or higher (OR: 21.29, 95% CI: 4.98-91.01), chronic obstructive pulmonary disease (OR: 7.25, 95% CI: 1.65-31.81), hypertension (OR: 2.98, 95% CI: 1.20-7.39), and use of immunoglobulin (OR: 5.26, 95% CI: 1.06-26.25). Conclusion: Our data suggests that the use of anti-angiogenic drugs may not exacerbate COVID-19 severity in NSCLC patients, indicating their potential safe application even during the pandemic period.

Evolving views on the first two ligands of the angiotensin II type 2 receptor. From putative antagonists to potential agonists?

The renin-angiotensin system is one of the most complex regulatory systems that controls multiple organ functions. One of its key components, angiotensin II (Ang II), stimulates two G-protein coupled class A receptors: the Ang II type 1 (AT1) receptor and the Ang II type 2 (AT2) receptor. While stimulation of the AT1 receptor causes G-protein-dependent signaling and arrestin recruitment, the AT2 receptor seems to have a constitutively active-like conformation and appears to act via G-protein-dependent and -independent pathways. Overstimulation of the AT1 receptor may lead to unwanted effects like inflammation and fibrosis. In contrast, stimulation of the AT2 receptor leads to opposite effects thus restoring the balance. However, the role of the AT2 receptor has become controversial due to beneficial effects of putative AT2 receptor antagonists. The two first synthetic AT2 receptor-selective ligands, peptide CGP42112 and small molecule PD123319, were initially both considered antagonists. CGP42112 was subsequently considered a partial agonist and it was recently demonstrated to be a full agonist. Based on the search-term PD123319 in Pubmed, 1652 studies have investigated putative AT2 receptor antagonist PD123319. Here, we put forward literature that shows beneficial effects of PD123319 alone, even at doses too low for antagonist efficacy. These beneficial effects appear compatible with agonist-like activity via the AT2 receptor. Taken together, a more consistent image of a therapeutic role of stimulated AT2 receptor emerges which may clarify current controversies.

Discovery of Efficient Hypoxia-Targeted NO Donor Compounds to Alleviate Hypoxia Cardiac Disease

In order to obtain efficient NO donor drugs to treat hypoxic cardiac disease, a series of hypoxia-targeted NO donor compounds were prepared and screened. Among them, a representative compound H3 was found to selectively release NO under hypoxia with a higher ratio than isosorbide dinitrate (ISDN). In vitro study indicated that H3 had a strong capability of alleviating vascular dilation and reducing myocardial hypoxic injury due to its effective regulation of vascular dilatation and myocardial injury-related proteins in H9c2 cells even at low concentrations. By intraperitoneal injection or intragastric administration, in vivo animal tests revealed that H3 possessed a potent antimyocardial hypoxic injury effect superior to ISDN. These findings suggest that H3 has a better effect on alleviating hypoxic cardiac disease than the conventional drug, owing to its hypoxia-targeted release of NO.

High resolution chest computed tomography findings in patients with clinically suspected COVID-19 pneumonia in Uganda: a cross-sectional study

Background

The alarming spread of the COVID-19 pandemic has led to a shortage of RT-PCR kits in Uganda necessitating the use of high-resolution chest Computed Tomography to guide patient management and treatment.

Main Objective

To describe the chest HRCT findings in patients with clinically suspected COVID-19 pneumonia and to compare its diagnostic accuracy to RT-PCR. .

Methods

In this cross-sectional study, chest HRCT findings of 384 patients and available RT-PCR laboratory results were reviewed and recorded in the data collection form.

Results

The commonest chest HRCT findings were bilateral ground glass opacities (78.2%). Out of the 31.7% patients that took the PCR test only 26.9% tested positive. 16 out of 17 patients who tested negative, were classified under CORADS 5.The sensitivity of chest HRCT was 90.4%, 95% CI (82.6-95.5), positive predictive value of 84.2%, 95% CI (75.6-90.7), and accuracy of 77.5%, 95% CI (71.5-87.1).

Conclusions

HRCT was found superior to RT-PCR in diagnosing COVID-19. A patient with positive HRCT findings should be treated as COVID 19 when RT-PCR is inaccessible or results are negative. A patient with negative HRCT requires complimentary RT-PCR and possibly follow up CT scans if symptoms persist before treating for COVID 19.

Novel AT2R agonist, β-Pro7Ang III, is cardio- and vaso-protective in diabetic spontaneously hypertensive rats

Stimulation of the angiotensin II type 2 receptor (AT2R) evokes protective effects in various cardiovascular diseases. Thus, this study aimed to investigate the effects of AT2R stimulation, with or without AT1R blockade, in a model of hypertension with concomitant type 1 diabetes mellitus (T1DM). Spontaneously hypertensive rats (SHRs) were given either citrate or a single dose of streptozotocin (STZ; 55 mg/kg, i.p.) to induce diabetes. After 4 weeks of diabetes, animals were administered either a vehicle (saline), AT2R agonist, β-Pro7Ang III (0.1 mg/kg/day via osmotic mini-pump), AT1R blocker, candesartan (2 mg/kg/day via drinking water), or a combination of both for a further 8 weeks. β-Pro7Ang III treatment had no effect on blood pressure, but attenuated the significant increase in cardiac interstitial collagen and protein expression of fibrotic and inflammatory markers, and superoxide levels that was evident in diabetic SHRs. These effects were not observed with candesartan, despite its blood pressure lowering effects. Although β-Pro7Ang III had no effect on aortic fibrosis, it significantly attenuated MCP-1 protein expression and superoxide levels when compared to both the non-diabetic and diabetic SHRs, to a similar extent as candesartan. In both the heart and vasculature, the effects of β-Pro7Ang III in combination with candesartan were similar to those of β-Pro7Ang III alone, and superior to candesartan alone. It was concluded that in hypertension with concomitant diabetes, AT2R stimulation with a novel ligand alone, or in combination with AT1R blockade, improved the cardiac and vascular structural changes that were strongly associated with inflammation and oxidative stress, independent of blood pressure regulation.

Potential therapeutic implications of calcitriol administration and weight reduction on CD4 T cell dysregulation and renin angiotensin system-associated acute lung injury in septic obese mice

This study investigated the effects of weight reduction and/or calcitriol administration on regulating CD4 T cell subsets and renin-angiotensin system (RAS)-associated acute lung injury (ALI) in obese mice with sepsis. Half of the mice were fed a high-fat diet for 16 weeks, half of them had high-fat diet for 12 weeks then were transferred to a low-energy diet for 4 weeks. After feeding the respective diets, cecal ligation and puncture (CLP) were performed to induce sepsis. There were four sepsis groups: OSS group, obese mice injected with saline; OSD group, obese mice given calcitriol; WSS group, mice with weight reduction and saline; WSD group, mice with weight reduction and calcitriol. Mice were sacrificed after CLP. The findings showed that CD4 T subsets distribution did not differ among the experimental groups. Calcitriol-treated groups had higher RAS-associated AT2R, MasR, ACE2, and angiopoietin 1-7 (Ang(1-7)) levels in the lungs. Also, higher tight junction proteins were noted 12 h after CLP. At 24 h post-CLP, weight reduction and/or calcitriol treatment reduced plasma inflammatory mediator production. Calcitriol-treated groups had higher CD4/CD8, T helper (Th)1/Th2 and lower Th17/regulatory T (Treg) ratios than the groups without calcitriol. In the lungs, calcitriol-treated groups had lower AT1R levels, whereas the RAS anti-inflammatory protein levels were higher than those groups without calcitriol. Lower injury scores were also noted at this time point. These findings suggested weight reduction decreased systemic inflammation. However, calcitriol administration produced a more-balanced Th/Treg distribution, upregulated the RAS anti-inflammatory pathway, and attenuated ALI in septic obese mice.

Differential expression of the angiotensin receptors (AT1, AT2, and AT4) in the placental bed of HIV-infected preeclamptic women of African ancestry

The Renin-Angiotensin-Aldosterone System (RAAS) is implicated in the pathophysiology of preeclampsia (PE). There is a paucity of data on uteroplacental angiotensin receptors AT1-2 and 4. We evaluated the immunoexpression of AT1R, AT2R, and AT4R within the placental bed of PE vs. normotensive (N) pregnancies stratified by HIV status. Placental bed (PB) biopsies (n = 180) were obtained from N and PE women. Both groups were stratified by HIV status and gestational age into early-and late onset-PE. Immuno-labeling of AT1R, AT2R, and AT4R was quantified using morphometric image analysis. Immunostaining of PB endothelial cells (EC) and smooth muscle cells of spiral arteries (VSMC) displayed an upregulation of AT1R expression compared to the N group (p < 0.0001). Downregulation of AT2R and AT4R expression was observed in PE vs. N group (p = 0.0042 and p < 0.0001), respectively. AT2R immunoexpression declined between HIV+ve and HIV-ve groups, while AT1R and AT4R displayed an increase. An increase in AT1R expression was noted in the EOPE-ve/+ve and LOPE-ve/+ve compared to N-ve/N+ve. In contrast, AT2R and AT4R expression decreased in EOPE-ve/+ve and LOPE-ve/+ve compared to N-ve/N+ve. We demonstrate a significant downregulation of AT2R and AT4R with a concomitant elevated AT1R immunoexpression within PB of HIV-infected PE women. In addition, a decline in AT2R and AT4R with an increase in AT1R immunoexpression in PE, EOPE, and LOPE vs. normotensive pregnancies, irrespective of HIV status. Thus highlighting differential immunoexpression of uteroplacental RAAS receptors based on pregnancy type, HIV status, and gestational age.

Severity-onset prediction of COVID-19 via artificial-intelligence analysis of multivariate factors

Progression to a severe condition remains a major risk factor for the COVID-19 mortality. Robust models that predict the onset of severe COVID-19 are urgently required to support sensitive decisions regarding patients and their treatments. In this study, we developed a multivariate survival model based on early-stage CT images and other physiological indicators and biomarkers using artificial-intelligence analysis to assess the risk of severe COVID-19 onset. We retrospectively enrolled 338 adult patients admitted to a hospital in China (severity rate, 31.9%; mortality rate, 0.9%). The physiological and pathological characteristics of the patients with severe and non-severe outcomes were compared. Age, body mass index, fever symptoms upon admission, coexisting hypertension, and diabetes were the risk factors for severe progression. Compared with the non-severe group, the severe group demonstrated abnormalities in biomarkers indicating organ function, inflammatory responses, blood oxygen, and coagulation function at an early stage. In addition, by integrating the intuitive CT images, the multivariable survival model showed significantly improved performance in predicting the onset of severe disease (mean time-dependent area under the curve = 0.880). Multivariate survival models based on early-stage CT images and other physiological indicators and biomarkers have shown high potential for predicting the onset of severe COVID-19.

Angiotensin II type 1a receptor knockout ameliorates high-fat diet-induced cardiac dysfunction by regulating glucose and lipid metabolism

Obesity-related cardiovascular diseases are associated with overactivation of the renin-angiotensin system (RAS). However, the underlying mechanisms remain elusive. In this study, we investigate the role of angiotensin II (Ang II) in high-fat diet (HFD)-induced cardiac dysfunction by focusing on cardiac glucose and lipid metabolism and energy supply. Ang II plays a role in cardiovascular regulation mainly by stimulating angiotensin II type 1 receptor (AT1R), among which AT1aR is the most important subtype in regulating the function of the cardiovascular system. AT1aR gene knockout (AT1aR ‒/‒) rats and wild-type (WT) rats are randomly divided into four groups and fed with either a normal diet (ND) or a HFD for 12 weeks. The myocardial lipid content, Ang II level and cardiac function are then evaluated. The expressions of a number of genes involved in glucose and fatty acid oxidation and mitochondrial dynamics are measured by quantitative polymerase chain reaction and western blot analysis. Our results demonstrate that AT1aR knockout improves HFD-induced insulin resistance and dyslipidemia as well as lipid deposition and left ventricular dysfunction compared with WT rats fed a HFD. In addition, after feeding with HFD, AT1aR ‒/‒ rats not only show further improvement in glucose and fatty acid oxidation but also have a reverse effect on increased mitochondrial fission proteins. In conclusion, AT1aR deficiency ameliorates HFD-induced cardiac dysfunction by enhancing glucose and fatty acid oxidation, regulating mitochondrial dynamics-related protein changes, and further promoting cardiac energy supply.

Sex differences in the renin-angiotensin-aldosterone system and its roles in hypertension, cardiovascular, and kidney diseases

Cardiovascular disease is a pathology that exhibits well-researched biological sex differences, making it possible for physicians to tailor preventative and therapeutic approaches for various diseases. Hypertension, which is defined as blood pressure greater than 130/80 mmHg, is the primary risk factor for developing coronary artery disease, stroke, and renal failure. Approximately 48% of American men and 43% of American women suffer from hypertension. Epidemiological data suggests that during reproductive years, women have much lower rates of hypertension than men. However, this protective effect disappears after the onset of menopause. Treatment-resistant hypertension affects approximately 10.3 million US adults and is unable to be controlled even after implementing ≥3 antihypertensives with complementary mechanisms. This indicates that other mechanisms responsible for modulating blood pressure are still unclear. Understanding the differences in genetic and hormonal mechanisms that lead to hypertension would allow for sex-specific treatment and an opportunity to improve patient outcomes. Therefore, this invited review will review and discuss recent advances in studying the sex-specific physiological mechanisms that affect the renin-angiotensin system and contribute to blood pressure control. It will also discuss research on sex differences in hypertension management, treatment, and outcomes.

Network-Based Prediction of Side Effects of Repurposed Antihypertensive Sartans against COVID-19 via Proteome and Drug-Target Interactomes

The potential of targeting the Renin-Angiotensin-Aldosterone System (RAAS) as a treatment for the coronavirus disease 2019 (COVID-19) is currently under investigation. One way to combat this disease involves the repurposing of angiotensin receptor blockers (ARBs), which are antihypertensive drugs, because they bind to angiotensin-converting enzyme 2 (ACE2), which in turn interacts with the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike protein. However, there has been no in silico analysis of the potential toxicity risks associated with the use of these drugs for the treatment of COVID-19. To address this, a network-based bioinformatics methodology was used to investigate the potential side effects of known Food and Drug Administration (FDA)-approved antihypertensive drugs, Sartans. This involved identifying the human proteins targeted by these drugs, their first neighbors, and any drugs that bind to them using publicly available experimentally supported data, and subsequently constructing proteomes and protein-drug interactomes. This methodology was also applied to Pfizer's Paxlovid, an antiviral drug approved by the FDA for emergency use in mild-to-moderate COVID-19 treatment. The study compares the results for both drug categories and examines the potential for off-target effects, undesirable involvement in various biological processes and diseases, possible drug interactions, and the potential reduction in drug efficiency resulting from proteoform identification.

Gut Microbiota Perturbation in Early Life Could Influence Pediatric Blood Pressure Regulation in a Sex-Dependent Manner in Juvenile Rats

The present study aimed to investigate whether gut dysbiosis induced by ceftriaxone in early life could influence pediatric blood pressure regulation in childhood with or without exposure to a high-fat diet (HFD). Sixty-three newborn pups of Sprague-Dawley rats were administered ceftriaxone sodium or saline solution until weaning at 3 weeks, and the rats were fed a HFD or regular diet from 3 to 6 weeks. Tail-cuff blood pressure, the expression levels of genes of the renin-angiotensin system (RAS), the concentrations of IL-1β, IL-6, and TNF-α in the colon and prefrontal cortex, and the composition of fecal microbiota were analyzed. Ceftriaxone treatment significantly increased the diastolic blood pressure of male rats at 3 weeks. At 6 weeks, systolic blood pressure (SBP) was significantly increased only in ceftriaxone treated male rats fed with HFD. The RAS showed increased activation in the kidney, heart, hypothalamus, and thoracic and abdominal aorta of male rats, but only in the kidney, heart, and hypothalamus of female rats. HFD-fed female rats showed a decreased level of IL-6 in the colon. α diversity of gut microbiota decreased and the Firmicutes to Bacteroidetes ratio increased in both male and female rats at 3 weeks; however, these parameters recovered to various degrees in female rats at 6 weeks. These results revealed that early-life gut dysbiosis induced by antibiotics combined with a HFD in childhood could be involved in pediatric blood pressure regulation and an increase in SBP in juvenile rats, and these effects occurred in a sex-dependent manner.

Signaling pathways in vascular function and hypertension: molecular mechanisms and therapeutic interventions

Hypertension is a global public health issue and the leading cause of premature death in humans. Despite more than a century of research, hypertension remains difficult to cure due to its complex mechanisms involving multiple interactive factors and our limited understanding of it. Hypertension is a condition that is named after its clinical features. Vascular function is a factor that affects blood pressure directly, and it is a main strategy for clinically controlling BP to regulate constriction/relaxation function of blood vessels. Vascular elasticity, caliber, and reactivity are all characteristic indicators reflecting vascular function. Blood vessels are composed of three distinct layers, out of which the endothelial cells in intima and the smooth muscle cells in media are the main performers of vascular function. The alterations in signaling pathways in these cells are the key molecular mechanisms underlying vascular dysfunction and hypertension development. In this manuscript, we will comprehensively review the signaling pathways involved in vascular function regulation and hypertension progression, including calcium pathway, NO-NOsGC-cGMP pathway, various vascular remodeling pathways and some important upstream pathways such as renin-angiotensin-aldosterone system, oxidative stress-related signaling pathway, immunity/inflammation pathway, etc. Meanwhile, we will also summarize the treatment methods of hypertension that targets vascular function regulation and discuss the possibility of these signaling pathways being applied to clinical work.

Vitamin D and COVID-19: where are we now?

The pandemic caused by the SARS-CoV-2 virus has triggered great interest in the search for the pathophysiological mechanisms of COVID-19 and its associated hyperinflammatory state. The presence of prognostic factors such as diabetes, cardiovascular disease, hypertension, obesity, and age influence the expression of the disease's clinical severity. Other elements, such as 25-hydroxyvitamin D (25(OH)D3) concentrations, are currently being studied. Various studies, mostly observational, have sought to demonstrate whether there is truly a relationship between 25(OH)D3 levels and the acquisition and/or severity of the disease. The objective of this study was to carry out a review of the current data that associate vitamin D status with the acquisition, evolution, and/or severity of infection by the SARS-CoV-2 virus and to assess whether prevention through vitamin D supplementation can prevent infection and/or improve the evolution once acquired. Vitamin D system has an immunomodulatory function and plays a significant role in various bacterial and viral infections. The immune function of vitamin D is explained in part by the presence of its receptor (VDR) and its activating enzyme 25-hydroxyvitamin D-1alpha-hydroxylase (CYP27B1) in immune cells. The vitamin D, VDR, and Retinoid X Receptor complex allows the transcription of genes with antimicrobial activities, such as cathelicidins and defensins. COVID-19 characteristically presents a marked hyperimmune state, with the release of proinflammatory cytokines such as IL-6, TNF-α, and IL-1β. Thus, there are biological factors linking vitamin D to the cytokine storm, which can herald some of the most severe consequences of COVID-19, such as acute respiratory distress syndrome. Hypovitaminosis D is widespread worldwide, so the prevention of COVID-19 through vitamin D supplementation is being considered as a possible therapeutic strategy easy to implement. However, more-quality studies and well-designed randomized clinical trials are needed to address this relevant question.

The mechanism of low-level arsenic exposure-induced hypertension: Inhibition of the activity of the angiotensin-converting enzyme 2

It is now well-established that arsenic exposure induces hypertension in humans. Although arsenic-induced hypertension is reported in many epidemiological studies, the underlying molecular mechanism of arsenic-induced hypertension is not fully characterized. In the human body, blood pressure is primarily regulated by a well-known physiological system known as the renin-angiotensin system (RAS). Hence, we explored the potential molecular mechanisms of arsenic-induced hypertension by investigating the regulatory roles of the RAS. Adult C57BL/6JJcl male mice were divided into four groups according to the concentration of arsenic in drinking water (0, 8, 80, and 800 ppb) provided for 8 weeks. Arsenic significantly raised blood pressure in arsenic-exposed mice compared to the control group, and significantly raised plasma MDA and Ang II and reduced Ang (1-7) levels. RT-PCR results showed that arsenic significantly downregulated ACE2 and MasR in mice aortas. In vitro studies of endothelial HUVEC cells treated with arsenic showed increased level of MDA and Ang II and lower levels of Ang (1-7), compared with the control. Arsenic significantly downregulated ACE2 and MasR expression, as well as those of Sp1 and SIRT1; transcriptional activators of ACE2, in HUVECs. Arsenic also upregulated markers of endothelial dysfunction (MCP-1, ICAM-1) and inflammatory cytokines (IL-6, TNF-α) in HUVECs. Our findings suggest that arsenic-induced hypertension is mediated, at least in part, by oxidative stress-mediated inhibition of ACE2 as well as by suppressing the vasoprotective axes of RAS, in addition to the activation of the classical axis.

Comorbidities, multimorbidity and COVID-19

The influence of comorbidities on COVID-19 outcomes has been recognized since the earliest days of the pandemic. But establishing causality and determining underlying mechanisms and clinical implications has been challenging-owing to the multitude of confounding factors and patient variability. Several distinct pathological mechanisms, not active in every patient, determine health outcomes in the three different phases of COVID-19-from the initial viral replication phase to inflammatory lung injury and post-acute sequelae. Specific comorbidities (and overall multimorbidity) can either exacerbate these pathological mechanisms or reduce the patient's tolerance to organ injury. In this Review, we consider the impact of specific comorbidities, and overall multimorbidity, on the three mechanistically distinct phases of COVID-19, and we discuss the utility of host genetics as a route to causal inference by eliminating many sources of confounding. Continued research into the mechanisms of disease-state interactions will be crucial to inform stratification of therapeutic approaches and improve outcomes for patients.

Exercise-induced expression of SARS-CoV-2 entry receptors: impact of mask modality, sex, and exercise intensity

BACKGROUND

Wearing a facemask affects physiological responses to exercise. We explored how exercising with a facemask affects the expression of SARS-CoV-2 entry receptor (angiotensin-converting enzyme 2 [ACE2]) and some associated genes (angiotensin type-1 receptors [AT<inf>1</inf>R]; Mas receptor [MasR]; hypoxia-inducible factor 1α [HIF-1α]; endothelial nitric oxide synthase [eNOS]) among healthy males and females.

METHODS

One hundred forty-four apparently healthy individuals (72 females; age: 30±6) were allocated to three mask groups of 48 (N95, Surgical, No Mask) with two exercise subgroups for each mask for both sexes. Participants in each experimental group performed either a submaximal (walking with no grade) or maximal (a modified Bruce Protocol) treadmill exercise test. Blood samples were collected before and after each exercise test and used to analyze the mRNA expression of the genes studied.

RESULTS

The post-exercise expression of genes examined were comparable between Surgical, N95, and No Mask (P>0.05). ACE2 was significantly greater in Surgical and N95 against No Mask at baseline and following moderate-intensity exercise (P<0.05). Whilst similar expressions were noted for MasR and eNOS (P>0.05), AT<inf>1</inf>R was greater in N95 than Surgical following high-intensity exercise (P<0.05). HIF-1α following either exercise intensity was significantly lower in N95 than Surgical (P<0.05). AT<inf>1</inf>R and HIF-1α were similar between Surgical and N95 against No Mask (P>0.05). ACE2 and AT<inf>1</inf>R were significantly higher in either mask modality than No Mask in males at baseline and postexercise (P<0.05). HIF-1α, MasR, and eNOS expressions were comparable between all mask groups in either sex (P<0.05).

CONCLUSIONS

Our findings suggest that wearing a facemask does not differentiate the gene expression of SARS-CoV-2 entry receptor following exercise among both sexes.

Relation of ACE2 with co-morbidity factors in SARS-CoV-2 pathogenicity

In the last 3 years of the pandemic situation, SARS-CoV-2 caused a significant number of deaths. Infection rates for symptomatic and asymptomatic patients are higher than that for death. Eventually, researchers explored that the major deaths are attributed to several comorbidity factors. The confounding factors and gender-associated infection/death rate are observed globally. This suggests that SARS-CoV-2 selects the human system recognizing the internal comorbid environment. This article explored the influences of hypertension, diabetes, cardiovascular, and renovascular disorders in COVID-19 severity and mortality. Brief mechanistic layouts have been presented here, indicating some of the comorbidity as the critical determinant in the COVID-19 pathogenesis and related mortality.

Association of RASis and HMG-CoA reductase inhibitors with clinical manifestations in coronavirus disease 2019 patients: Results from the Khorshid Coronavirus Disease Cohort Study

Background

Angiotensin II receptor blockers (ARBs) and angiotensin-converting enzyme inhibitors (ACEinhs) may deteriorate or improve the clinical manifestations in severe acute respiratory syndrome coronavirus 2 infection. A comparative, cross-sectional study was conducted to evaluate the association of ARBs/ACEinhs and hydroxy-3-methyl-glutaryl-CoA reductase inhibitors (HMGRis) with clinical outcomes in coronavirus disease 2019 (COVID-19).

Materials and Methods

From April 4 to June 2, 2020, 659 patients were categorized according to whether they were taking ARB, ACEinh, or HMGRi drugs or none of them. Demographic variables, clinical and laboratory tests, chest computed tomography findings, and intensive care unit-related data were analyzed and compared between the groups.

Results

The ARB, ACEinh, and HMGRi groups significantly had lower heart rate (P < 0.05). Furthermore, a lower percent of O₂ saturation (89.34 ± 7.17% vs. 84.25 ± 7.00%; P = 0.04) was observed in the ACEis group than non-ACEinhs. Mortality rate and the number of intubated patients were lower in patients taking ARBs, ACEinhs, and HMGRis, although these differences failed to reach statistical significance.

Conclusion

Our findings present clinical data on the association between ARBs, ACEinhs, and HMGRis and outcomes in hospitalized, hypertensive COVID-19 patients, implying that ARBs/ACEinhs are not associated with the severity or mortality of COVID-19 in such patients.

Influencing factors of nucleic acid negative conversion in patients with mild and common COVID-19 induced by the Omicron variant of SARS-COV-2

OBJECTIVE

To observe the clinical characteristics of mild and common COVID-19 patients infected with the Omicron variant, and to analyze related factors affecting the time to negative conversion of viral nucleic acid detection.

METHODS

Clinical data of 1781 patients with coronavirus disease 2019 (COVID-19) admitted to a cabin hospital in Shanghai from April 12 to May 26, 2022, were retrospectively analyzed, including age, gender, height, weight, clinical symptoms, comorbid diseases, COVID-19 vaccination, treatment, and nucleic acid negative conversion time. Univariate and multivariate logistic regression analyses were used to analyze the influencing factors of nucleic acid negative conversion time.

RESULTS

Among the 1781 patients, 995 were male and 786 were female, with a median age of 39 (30, 52) years. There were 727 patients (40.8%) with overweight and obesity [body mass index (BMI) > 24 kg/cm 2) and 413 patients (23.2%) had comorbid diseases. 205 cases (11.5%) were not vaccinated while 1576 cases were vaccinated. There were 1233 cases (69.2%) with one or more symptoms. The main clinical symptoms were cough (60.3%), expectoration (50.4%) and fever (36.9%). 1444 cases (81.0%) were treated with Chinese medicine, 78 cases (4.4%) were treated with western medicine, 14 cases (0.8%) were treated with integrated Chinese and western medicine, and 245 cases (13.8%) did not receive any medical treatment. All patients improved and were discharged. The median nucleic acid negative conversion time was 10.3 (7.4, 12.4) d. Univariate and multivariate analysis showed that, age ≥ 60 years ( OR＝1.537, 95% CI: 1.116 - 2.115, P<0.01), BMI > 24 kg/cm 2 ( OR＝1.344, 95% CI: 1.106 - 1.634, P<0.01 ) and hypertension ( OR＝1.518, 95% CI: 1.094 - 2.106, P<0.05) were independent risk factors for prolonged nucleic acid negative conversion. COVID-19 vaccination ( OR=0.548, 95% CI: 0.398 - 0.755, P<0.01) was a protective factor, that is, vaccination shortened the time for the nucleic acid test to become negative.

CONCLUSIONS

The symptoms of the Omicron variant infection were relatively mild and occult. Age ≥ 60 years old, comorbid hypertension, no vaccination and BMI > 24 kg/cm 2 are independent influencing factors for prolonged nucleic acid negative conversion.

Crosstalk between SARS-CoV-2 Infection and Type II Diabetes

Since the outbreak of coronavirus disease (COVID-19) in Wuhan, China, triggered by severe acute respiratory coronavirus 2 (SARS-CoV-2) in late November 2019, spreading to more than 200 countries of the world, the ensuing pandemic to an enormous loss of lives, mainly the older population with comorbidities, like diabetes, cardiovascular disease, chronic obstructive pulmonary disease, obesity, and hypertension. Amongst these immune-debilitating diseases, SARS-CoV-2 infection is the most common in patients with diabetes due to the absence of a normal active immune system to fight the COVID-19. Recovery of patients having a history of diabetes from COVID-19 encounters several complications, and their management becomes cumbersome. For control of coronavirus, antiviral medications, glucose-lowering agents, and steroids have been carefully evaluated. In the present review, we discuss the crosstalk between SARS-CoV-2 infection and patients with a history of diabetes. We mainly emphasize the molecular factors that are involved in diabetic individuals recently infected by SARS-CoV-2 and developed COVID-19 disease. Lastly, we examine the medications available for the long-term management of diabetic patients with SARS-CoV-2 infection.

Emerging complications of COVID-19 in a subset of Indian population: a pathological review with clinico-radiological case scenarios

Background

Coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which was declared a pandemic by the World Health Organization on 11 March 2020 has been reported in most countries around the world since its origins in Wuhan, China. As of September 2021, there have been over 229 million cases of COVID-19 reported worldwide, with over 4.7 million COVID-19–associated deaths.

Body

The devastating second wave of the COVID-19 pandemic in India has seen a rise in various extrapulmonary manifestations. One of key components in the pathogenesis of COVID-19 is downregulation of ACE-2, which is expressed on many organs and counterbalances the pro-inflammatory effects of ACE/angiotensin-II axis. This leads to influx of inflammatory cells into alveoli, increased vascular permeability and activation of prothrombotic mediators. Imaging findings such as ground glass opacities, interlobular septal thickening, vascular dilatation and pulmonary thrombosis correlate well with the pathogenesis.

Conclusion

We hypothesize that the systemic complications of COVID-19 are caused by either direct viral invasion or effect of cytokine storm leading to inflammation and thrombosis or a combination of both. Gaining insights into pathobiology of SARS-CoV-2 will help understanding the various multisystemic manifestations of COVID-19. To date, only a few articles have been published that comprehensively describe the pathophysiology of COVID-19 along with its various multisystemic imaging manifestations.

Angiotensin-(1–9) prevents angiotensin II-induced endothelial apoptosis through CNPY2/PERK pathway

Endothelial apoptosis caused by activation of renin-angiotensin system (RAS) plays a vital part in the occurrence and progress of hypertension. Angiotensin-(1-9) (Ang-(1-9)) is a peptide of the counter-regulatory non-classical RAS with anti-hypertensive effects in vascular endothelial cells (ECs). However, the mechanism of action remains unclear. Considering that the endothelial apoptosis was closely related to endoplasmic reticulum stress (ERS) and mitochondrial function. Herein, we aimed to elucidate the effects of Ang-(1-9) on endothelial apoptosis and the underlying molecular mechanism in angiotensin II (Ang II) induced hypertension. In human umbilical vascular endothelial cells (HUVECs), we observed Ang-(1-9) inhibited Ang II-induced ERS associated endothelial apoptosis. Mechanically, Ang-(1-9) inhibited endothelial apoptosis by blocking CNPY2/PERK mediated CaMKII/Drp1-dependent mitochondrial fission and eIF2α/CHOP signal. Consistent with above effects in HUVECs, in Ang II-induced hypertensive mice, we found administration of exogenous Ang-(1-9) attenuated endothelial apoptosis and arterial blood pressure, which were mediated by CNPY2/PERK signaling pathway. Our study indicated Ang-(1-9) inhibited Ang II-induced hypertension through CNPY2/PERK pathway. These findings may provide new insights for prevention and treatment of hypertension in future.

The Heart as a Target of Vasopressin and Other Cardiovascular Peptides in Health and Cardiovascular Diseases

The automatism of cardiac pacemaker cells, which is tuned, is regulated by the autonomic nervous system (ANS) and multiple endocrine and paracrine factors, including cardiovascular peptides. The cardiovascular peptides (CPs) form a group of essential paracrine factors affecting the function of the heart and vessels. They may also be produced in other organs and penetrate to the heart via systemic circulation. The present review draws attention to the role of vasopressin (AVP) and some other cardiovascular peptides (angiotensins, oxytocin, cytokines) in the regulation of the cardiovascular system in health and cardiovascular diseases, especially in post-infarct heart failure, hypertension and cerebrovascular strokes. Vasopressin is synthesized mostly by the neuroendocrine cells of the hypothalamus. There is also evidence that it may be produced in the heart and lungs. The secretion of AVP and other CPs is markedly influenced by changes in blood volume and pressure, as well as by other disturbances, frequently occurring in cardiovascular diseases (hypoxia, pain, stress, inflammation). Myocardial infarction, hypertension and cardiovascular shock are associated with an increased secretion of AVP and altered responsiveness of the cardiovascular system to its action. The majority of experimental studies show that the administration of vasopressin during ventricular fibrillation and cardiac arrest improves resuscitation, however, the clinical studies do not present consisting results. Vasopressin cooperates with the autonomic nervous system (ANS), angiotensins, oxytocin and cytokines in the regulation of the cardiovascular system and its interaction with these regulators is altered during heart failure and hypertension. It is likely that the differences in interactions of AVP with ANS and other CPs have a significant impact on the responsiveness of the cardiovascular system to vasopressin in specific cardiovascular disorders.

COVID-19 in pregnancy: possible mechanisms not to be discounted

SARS-CoV-2 has infected more than 16 million people worldwide. Related complications and death from COVID-19 disease and their underlying pathophysiology are intensely investigated. Pregnant women are among the affected. Although the severity of disease in pregnancy does not appear to be increased, the effects of infection on pregnancy should not escape careful examination. The currently known receptor for the virus, ACE2, regulates the renin-angiotensin system and is increased during pregnancy. Virus-receptor interactions may have significant effects on placental function, fetal development, and maternal immunity. The manifestation of cardiovascular complications of infection produces the hypothesis that a significant effect of the virus may be its influence on the maternal vascular system. Interference with the vascular adaptations to pregnancy and the post-partum may have implications for concurrent and future pregnancies as well as for long-term cardiovascular health. We should not miss the opportunity to learn from this virus about the physiology of pregnancy.

Predictive value of hematological and inflammatory markers for severity of COVID-19

Introduction and Aim: Coronavirus disease 2019 (COVID–19) can cause damage to a wide variety of organs throughout the body, with the lung being its primary focus of attack. The identification of prognostic indicators in COVID-19 can be of assistance in the management of the disease, in instances that are critical or severe. The purpose of this study was to investigate the hematological and inflammatory indicators in COVID-19 patients who were hospitalized and determine how closely those markers are associated with the severity of the condition.   Materials and Methods: In this cross-sectional prospective analysis, there were a total of 200 patients diagnosed with COVID-19. The demographic information and comorbidities of the patients were gathered through direct questioning. The indicators of the complete blood count were recorded for every patient. In addition, tests were performed on D-dimer, ferritin, erythrocyte sedimentation rate (ESR), lactate dehydrogenase (LDH), and C reactive protein (CRP). Systemic immune inflammation index (SII) was calculated. The association of demographic and laboratory parameters with patient’s outcome evaluated.    Results: After a 30-day follow-up, 32 patients (16%) out of 200 required ICU hospitalization, with eight of them (4%) dying. Each of the following od diabetes (OR=4.2; 95 % CI= 1.8-2291, p=0.021), hypertension (OR=3.1, 95 % CI=1.21-19.11, p=0.033), D-dimmer (OR=3.22, 95 % CI=1.43-9.12, p=0.037), ferritin (OR=2.18, 95 % CI=1.4-7.22, p=0.027), NLR (OR=3.26, 95% CI=1.5-7.18, p= 0.023), LDH (OR= 6.23, 95% CI=1.77-22.9, p=0.034), and CRP (OR=4.56, 95% CI=1.32-28.85, p=0.007), were independent risk factors for severity of COVID-19.   Conclusion: The comorbidities diabetes and hypertension, as well as the levels of D-dimer, serum ferritin, NLR, LDH, and CRP, could be utilized to predict COVID-19 severity and its outcome.

Understanding the pivotal roles of ACE2 in SARS-CoV-2 infection: from structure/function to therapeutic implication

In December 2019, a novel respiratory tract infection, from severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), was detected in China that rapidly spread around the world. This virus possesses spike (S) glycoproteins on the surface of mature virions, like other members of coronaviridae. The S glycoprotein is a crucial viral protein for binding, fusion, and entry into the target cells. Binding the receptor-binding domain (RBD) of S protein to angiotensin-converting enzyme 2 (ACE 2), a cell-surface receptor, mediates virus entry into cells; thus, understanding the basics of ACE2 and S protein, their interactions, and ACE2 targeting could be a potent priority for inhibition of virus infection. This review presents current knowledge of the SARS-CoV-2 basics and entry mechanism, structure and organ distribution of ACE2, and also its function in SARS-CoV-2 entry and pathogenesis. Furthermore, it highlights ACE2 targeting by recombinant ACE2 (rACE2), ACE2 activators, ACE inhibitor, and angiotensin II (Ang II) receptor blocker to control the SARS-CoV-2 infection.

A prospective longitudinal study evaluating the influence of immunosuppressives and other factors on COVID-19 in autoimmune rheumatic diseases

Background

We conducted this study to identify the influence of prolonged use of hydroxychloroquine (HCQ), glucocorticoids and other immunosuppressants (IS) on occurrence and outcome of COVID-19 in patients with autoimmune rheumatic diseases (AIRDs).

Methods

This was a prospective, multicenter, non-interventional longitudinal study across 15 specialist rheumatology centers. Consecutive AIRD patients on treatment with immunosuppressants were recruited and followed up longitudinally to assess parameters contributing to development of COVID-19 and its outcome.

Results

COVID-19 occurred in 314 (3.45%) of 9212 AIRD patients during a median follow up of 177 (IQR 129, 219) days. Long term HCQ use had no major impact on the occurrence or the outcome of COVID-19. Glucocorticoids in moderate dose (7.5–20 mg/day) conferred higher risk (RR = 1.72) of infection. Among the IS, Mycophenolate mofetil (MMF), Cyclophosphamide (CYC) and Rituximab (RTX) use was higher in patients with COVID 19. However, the conventional risk factors such as male sex (RR = 1.51), coexistent diabetes mellitus (RR = 1.64), pre-existing lung disease (RR = 2.01) and smoking (RR = 3.32) were the major contributing risk factors for COVID-19. Thirteen patients (4.14%) died, the strongest risk factor being pre-existing lung disease (RR = 6.36, p = 0.01). Incidence (17.5 vs 5.3 per 1 lakh (Karnataka) and 25.3 vs 7.9 per 1 lakh (Kerala)) and case fatality (4.1% vs 1.3% (Karnataka) and 4.3% vs 0.4% (Kerala)) rate of COVID-19 was significantly higher (p < 0.001) compared to the general population of the corresponding geographic region.

Conclusions

Immunosuppressants have a differential impact on the risk of COVID-19 occurrence in AIRD patients. Older age, males, smokers, hypertensive, diabetic and underlying lung disease contributed to higher risk. The incidence rate and the case fatality rate in AIRD patients is much higher than that in the general population.

Supplementary Information

The online version contains supplementary material available at 10.1186/s41927-022-00264-0.

Vasoconstrictor and Pressor Effects of Des-Aspartate-Angiotensin I in Rat

This study investigated the vasoactive effects of des-aspartate-angiotensin-I (DAA-I) in male Wistar rats on whole body vascular bed, isolated perfused kidneys, and aortic rings. Dose–response curves to DAA-I were compared with those to angiotensin II (Ang II). The Ang II-type-1 (AT1) receptor blocker, losartan, was used to evaluate the role of AT1 receptors in the responses to DAA-I. Studies were also conducted of the responsiveness in aortic rings after endothelium removal, nitric oxide synthase inhibition, or AT2 receptor blockade. DAA-I induced a dose-related systemic pressor response that was shifted to the right compared with Ang II. Losartan markedly attenuated the responsiveness to DAA-I. DAA-I showed a similar pattern in renal vasculature and aortic rings. In aortic rings, removal of endothelium and nitric oxide inhibition increased the sensitivity and maximal response to DAA-I and Ang II. AT2 receptor blockade did not significantly affect the responsiveness to DAA-I. According to these findings, DAA-I increases the systemic blood pressure and vascular tone in conductance and resistance vessels via AT1 receptor activation. This vasoconstrictor effect of DAA-I participates in the homeostatic control of arterial pressure, which can also contribute to the pathogenesis of hypertension. DAA-I may therefore be a potential therapeutic target in cardiovascular disease.

Involvement of the Renin-Angiotensin System in Stress: State of the Art and Research Perspectives

BACKGROUND

Along with other canonical systems, the renin-angiotensin system (RAS) has shown important roles in stress. This system is a complex regulatory proteolytic cascade composed of various enzymes, peptides, and receptors. Besides the classical (ACE/Ang II/AT1 receptor) and the counter-regulatory (ACE2/Ang-(1-7)/Mas receptor) RAS axes, evidence indicates that nonclassical components, including Ang III, Ang IV, AT₂ and AT₄, can also be involved in stress.

OBJECTIVE AND METHODS

This comprehensive review summarizes the current knowledge on the participation of RAS components in different adverse environmental stimuli stressors, including air jet stress, cage switch stress, restraint stress, chronic unpredictable stress, neonatal isolation stress, and post-traumatic stress disorder.

RESULTS AND CONCLUSION

In general, activation of the classical RAS axis potentiates stress-related cardiovascular, endocrine, and behavioral responses, while the stimulation of the counter-regulatory axis attenuates these effects. Pharmacological modulation in both axes is optimistic, offering promising perspectives for stress-related disorders treatment. In this regard, angiotensin-converting enzyme inhibitors and angiotensin receptor blockers are potential candidates already available since they block the classical axis, activate the counter-regulatory axis, and are safe and efficient drugs.

Paradox of COVID-19 in pregnancy: are pregnant women more protected against or at elevated risk of severe COVID-19?

Many underlying medical conditions have been linked to worse COVID-19 prognosis. Based on reports on SARS-CoV-1 and Middle East respiratory syndrome infections, pregnancy has been considered a predisposing factor to severe COVID-19, with pregnant women being a high-risk group for several physiological reasons. Specifically, pregnant women undergo physiological adaptations that predispose them to severe respiratory viral diseases, including SARS-CoV-2. However, a significant amount of evidence suggests that the clinical outcome of COVID-19 among pregnant women is not different from the general population. In view of this, this report discusses the physiological conditions in pregnant women that adversely affect their immunity, cardiovascular homeostasis, and their endothelial and coagulopathic functions, thereby making them more prone to severe viral infections. We also discuss how these physiological adaptations appear to paradoxically offer protection against severe COVID-19 among pregnant women.

The innate immune response, microenvironment proteinases, and the COVID-19 pandemic: pathophysiologic mechanisms and emerging therapeutic targets

The coronavirus disease 2019 (COVID-19) pandemic, causing considerable mortality and morbidity worldwide, has fully engaged the biomedical community in attempts to elucidate the pathophysiology of COVID-19 and develop robust therapeutic strategies. To this end, the predominant research focus has been on the adaptive immune response to COVID-19 infections stimulated by mRNA and protein vaccines and on the duration and persistence of immune protection. In contrast, the role of the innate immune response to the viral challenge has been underrepresented. This overview focuses on the innate immune response to COVID-19 infection, with an emphasis on the roles of extracellular proteases in the tissue microenvironment. Proteinase-mediated signaling caused by enzymes in the extracellular microenvironment occurs upstream of the increased production of inflammatory cytokines that mediate COVID-19 pathology. These enzymes include the coagulation cascade, kinin-generating plasma kallikrein, and the complement system, as well as angiotensin-generating proteinases of the renin–angiotensin system. Furthermore, in the context of several articles in this Supplement elucidating and detailing the trajectory of diverse profibrotic pathways, we extrapolate these insights to explore how fibrosis and profibrotic pathways participate importantly in the pathogenesis of COVID-19. We propose that the lessons garnered from understanding the roles of microenvironment proteinases in triggering the innate immune response to COVID-19 pathology will identify potential therapeutic targets and inform approaches to the clinical management of COVID-19. Furthermore, the information may also provide a template for understanding the determinants of COVID-19–induced tissue fibrosis that may follow resolution of acute infection (so-called “long COVID”), which represents a major new challenge to our healthcare systems.

The Role of Vitamin D in Supporting Health in the COVID-19 Era

The genomic activity of vitamin D is associated with metabolic effects, and the hormone has a strong impact on several physiological functions and, therefore, on health. Among its renowned functions, vitamin D is an immunomodulator and a molecule with an anti-inflammatory effect, and, recently, it has been much studied in relation to its response against viral infections, especially against COVID-19. This review aims to take stock of the correlation studies between vitamin D deficiency and increased risks of severe COVID-19 disease and, similarly, between vitamin D deficiency and acute respiratory distress syndrome. Based on this evidence, supplementation with vitamin D has been tested in clinical trials, and the results are discussed. Finally, this study includes a biochemical analysis on the effects of vitamin D in the body's defense mechanisms against viral infection. In particular, the antioxidant and anti-inflammatory functions are considered in relation to energy metabolism, and the potential, beneficial effect of vitamin D in COVID-19 is described, with discussion of its influence on different biochemical pathways. The proposed, broader view of vitamin D activity could support a better-integrated approach in supplementation strategies against severe COVID-19, which could be valuable in a near future of living with an infection becoming endemic.

The cross-talk between mucormycosis, steroids and diabetes mellitus amidst the global contagion of COVID-19

Mucormycosis is an opportunistic fungal disease that targets individuals having an impaired immune system due to a wide array of risk factors including HIV-AIDS, immunosuppressive therapy, diabetes mellitus, etc. The current explosive outbreak of coronavirus disease 2019 (COVID-19) has become the latest threat to such patients who are already susceptible to secondary infections. Physiological outcomes of COVID-19 end up in a cascade of grave alterations to the immunological profile and irreparable harm to their respiratory passage, heart and kidneys. Corticosteroidal treatment facilitates faster recovery and alleviates the adverse pathological effects of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). But clinical reports lend this approach a darker perspective especially if these patients have pre-existing diabetes mellitus. The mucormycotic fungal genera belonging to the order Mucorales not only survive but thrive under the comorbidity of COVID-19 and diabetes, often staying undetected until they have inflicted irreversible damage. Steroidal usage has been noted to be a common thread in the sudden spurt in secondary fungal infections among COVID-19 cases. Once considered a rare occurrence, mucormycosis has now acquired a notoriously lethal status in mainstream medical hierarchy. We set out to investigate whether corticosteroidal therapy against COVID-19 emboldens the development of mucormycosis. We also assess the conditions brought forth by steroidal usage and uncontrolled progression of diabetes in COVID-19 cases and their effect on the susceptibility towards mucormycosis.

Treatment of COVID-19 in Hemodialysis Patients Using Traditional Chinese Medicine: A Single-Center, Retrospective Study

Background: To explore the effect of combining traditional Chinese medicine (TCM) and Western medicine in hemodialysis patients with coronavirus disease 2019 (COVID-19).

Methods: This study was conducted from 27 January 2020 to 17 March 2020 in Wuhan Third Hospital Guanggu Branch, Wuhan, China. Fifty-three patients were included and divided into a control group (CG), which received Western medicine and a combined treatment group, which received TCM and Western medicine (TG). Clinical and laboratory data, TCM symptom scores, and chest computed tomography results were extracted and compared between the two groups.

Results: The TG included 21 (67.7%) men and 10 (32.3%) women with a mean age of 61.02 (standard deviation [SD] 15.07, range 26–89) years. The mean dialysis duration in the TG was 49 (SD 31) months. Of all patients in the TG, 27 (87.1%) had fatigue, 18 (58.1%) had dry cough, 16 (51.6%) had anorexia, 11 (35.5%) had dyspnea, and 11 (35.5%) had fever. The CG included 14 (63.6%) men and 8 (36.4%) women with a mean age of 61.45 (SD 13.78, range 36–84) years. The mean dialysis duration in the CG was 63 (SD 46) months. Of all patients in the CG, 21 (95.5%) had fatigue, 12 (54.5%) had dry cough, 17 (77.3%) had anorexia, 12 (54.5%) had dyspnea, and 7 (31.8%) had fever. After treatment, the TCM symptom scores of the two groups decreased; the anorexia scores were lower in the TG than in the CG (p < 0.05). After treatment, albumin increased and D-dimer, C-reactive protein, and lactate dehydrogenase levels decreased in the TG. The d-dimer levels were lower and the albumin level was higher in the TG than in the CG after treatment (p < 0.05). The cure rate was higher, and the mortality rate was lower in the TG than in the CG (p < 0.05).

Conclusion: A combination of TCM and Western medicine in hemodialysis patients with COVID-19 could relieve symptoms and help recovery. Further evidence from larger randomized controlled trials is needed to confirm our results.

Allele С (rs5186) of at1r is associated with the severity of COVID-19 in the Ukrainian population

INTRODUCTION

The severity of SARS-CoV-2 induced coronavirus disease 19 (COVID-19) depends on the presence of risk factors and the hosts' gene variability. There are preliminary results that gene polymorphisms of the renin-angiotensin system can influence the susceptibility to and mortality from COVID-19. Angiotensin II type 1 receptor (AT1R) might be a gene candidate that exerts such influence. The aim of this study was to elaborate on the association between A1166C at1r polymorphic variants and the susceptibility to and severity of COVID-19 in the Ukrainian population.

METHODS

The study population consisted of the Ukrainian population (Poltava region) with COVID-19, divided into three clinical groups in accordance with oxygen requirement: patients without oxygen therapy (n = 110), with non-invasive (n = 136) and invasive (n = 36) oxygen therapy. The A1166C polymorphism of the at1r was determined by polymerase chain reaction with subsequent restrictase analysis. In an attempt to better explain the role of the A1166C at1r polymorphism we compared its association with COVID-19, essential hypertension (n = 79), renoparenchimal hypertension (n = 30) and dyscirculatory encephalopathy (n = 112). The data for this comparison were obtained by meta-analysis.

RESULTS

We observed significant differences in the frequency of AA, AC and CC genotypes in the groups of COVID-19 patients with non-invasive and invasive oxygen therapy in comparison with control subjects as well as in the frequency of combined AC + CC genotype between the groups of COVID-19 patients with any types of oxygen therapy and patients without oxygen therapy. The frequency of the 1166C allele was higher in COVID-19 patients with invasive oxygen therapy (OR = 2.06; CI (1.20-3.53); p = 0.013). We obtained important results indicating that there were no differences between the frequency of at1r polymorphisms in patients with cardiovascular disease and severe COVID-19 with invasive oxygen therapy as well as those who died due to COVID-19.

CONCLUSION

Our study indicated the presence of an association between the A1166C at1r polymorphisms and the severity of COVID-19 in the Ukrainian population. It seems that in carriers of 1166C at1r, the severity of COVID-19 and oxygen dependency is higher as compared to the A allele carriers, possibly, due to cardiovascular disorders.