Understanding the role of nACE2 in neurogenic hypertension among COVID-19 patients

Exaggerated blood pressure elevation in response to orthostatic challenge, a post-acute sequelae of SARS-CoV-2 infection (PASC) after hospitalization

OBJECTIVE

Post-acute sequelae of SARS-COV-2 (PASC) are emerging as a major health challenge. Orthostatic intolerance secondary to autonomic failure has been found in PASC patients. This study investigated the effect of COVID-19 after recovery on blood pressure (BP) during the orthostatic challenge.

RESEARCH DESIGN AND METHODS

Thirty-one out of 45 patients hospitalized due to COVID-19-related pneumonia that developed PASC and did not have hypertension at discharge were studied. They underwent a head-up tilt test (HUTT) at 10.8 ± 1.9 months from discharge. All met the PASC clinical criteria, and an alternative diagnosis did not explain the symptoms. This population was compared with 32 historical asymptomatic healthy controls.

RESULTS

Exaggerated orthostatic blood pressure response (EOPR)/orthostatic hypertension (OHT) was detected in 8 out of 23 (34.7 %) patients, representing a significantly increased prevalence (7.67-fold increase p = 0.009) compared to 2 out of 32 (6.4 %) asymptomatic healthy controls matched by age, who underwent HUTT and were not infected with SARS-CoV-2.

CONCLUSIONS

This prospective evaluation in patients with PASC revealed abnormal blood pressure rise during the orthostatic challenge, suggesting of autonomic dysfunction in a third of the studied subjects. Our findings support the hypothesis that EOPR/OHT may be a phenotype of neurogenic hypertension. Hypertension in PASC patients may adversely affect the cardiovascular burden in the world.

Role of the renin-angiotensin system in the development of COVID-19-associated neurological manifestations

SARS-CoV-2 causes COVID-19, which has claimed millions of lives. This virus can infect various cells and tissues, including the brain, for which numerous neurological symptoms have been reported, ranging from mild and non-life-threatening (e.g., headaches, anosmia, dysgeusia, and disorientation) to severe and life-threatening symptoms (e.g., meningitis, ischemic stroke, and cerebral thrombosis). The cellular receptor for SARS-CoV-2 is angiotensin-converting enzyme 2 (ACE2), an enzyme that belongs to the renin-angiotensin system (RAS). RAS is an endocrine system that has been classically associated with regulating blood pressure and fluid and electrolyte balance; however, it is also involved in promoting inflammation, proliferation, fibrogenesis, and lipogenesis. Two pathways constitute the RAS with counter-balancing effects, which is the key to its regulation. The first axis (classical) is composed of angiotensin-converting enzyme (ACE), angiotensin (Ang) II, and angiotensin type 1 receptor (AT1R) as the main effector, which -when activated- increases the production of aldosterone and antidiuretic hormone, sympathetic nervous system tone, blood pressure, vasoconstriction, fibrosis, inflammation, and reactive oxygen species (ROS) production. Both systemic and local classical RAS' within the brain are associated with cognitive impairment, cell death, and inflammation. The second axis (non-classical or alternative) includes ACE2, which converts Ang II to Ang-(1-7), a peptide molecule that activates Mas receptor (MasR) in charge of opposing Ang II/AT1R actions. Thus, the alternative RAS axis enhances cognition, synaptic remodeling, cell survival, cell signal transmission, and antioxidant/anti-inflammatory mechanisms in the brain. In a physiological state, both RAS axes remain balanced. However, some factors can dysregulate systemic and local RAS arms. The binding of SARS-CoV-2 to ACE2 causes the internalization and degradation of this enzyme, reducing its activity, and disrupting the balance of systemic and local RAS, which partially explain the appearance of some of the neurological symptoms associated with COVID-19. Therefore, this review aims to analyze the role of RAS in the development of the neurological effects due to SARS-CoV-2 infection. Moreover, we will discuss the RAS-molecular targets that could be used for therapeutic purposes to treat the short and long-term neurological COVID-19-related sequelae.

Comprehensive role of SARS-CoV-2 spike glycoprotein in regulating host signaling pathway

Since the outbreak of coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, global public health and the economy have suffered unprecedented damage. Based on the increasing related literature, the characteristics and pathogenic mechanisms of the virus, and epidemiological and clinical features of the disease are being rapidly discovered. The spike glycoprotein (S protein), as a key antigen of SARS-CoV-2 for developing vaccines, antibodies, and drug targets, has been shown to play an important role in viral entry, tissue tropism, and pathogenesis. In this review, we summarize the molecular mechanisms of interaction between S protein and host factors, especially receptor-mediated viral modulation of host signaling pathways, and highlight the progression of potential therapeutic targets, prophylactic and therapeutic agents for prevention and treatment of SARS-CoV-2 infection.

Multi-Data Integration Towards a Global Understanding of the Neurological Impact of Human Brain Severe Acute Respiratory Syndrome Coronavirus 2 Infection

As the COVID-19 pandemic continues to unfold, numerous neurological symptoms emerge. The literature reports more and more manifestations of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) related to headache, dizziness, impaired consciousness, cognitive impairment, and motor disorders. Moreover, the infection of SARS-CoV-2 may have a durable neurological impact. ACE2/TMPRSS2 is the main entry point into cells for some strains of coronaviruses (CoVs), including SARS-CoV-2, which uses it to target the central nervous system (CNS). The aim of this study was to characterize the scope of the potential complex impact of a SARS-CoV-2 infection in the brain. It concerns different scales: the topographic, cognitive, sensorimotor, and genetic one. We investigated which cognitive and sensorimotor functions are associated with the brain regions where ACE2/TMPRSS2 is overexpressed, hypothesising that they might be particularly affected by the infection. Furthermore, overexpressed genes in these regions are likely to be impacted by COVID-19. This general understanding is crucial to establish the potential neurological manifestations of the infection. Data on mRNA expression levels of genes were provided by the Allen Institute for Brain Science (AIBS), and the localisation of brain functions by the LinkRbrain platform. The latter was also used to analyze the spatial overlap between ACE2/TMPRSS2 overexpression, and either function-specific brain activations or regional overexpression of other genes. The characterisation of these overexpressed genes was based on the GeneCards platform and the gene GSE164332 from the Gene Expression Omnibus database. We analysed the cognitive and sensorimotor functions whose role might be impaired, of which 88 have been categorised into seven groups: memory and recollection, motor function, pain, lucidity, emotion, sensory, and reward. Furthermore, we categorised the genes showing a significant increase in concentration of their mRNAs in the same regions where ACE2/TMPRSS2 mRNA levels are the highest. Eleven groups emerged from a bibliographical research: neurodegenerative disease, immunity, inflammation, olfactory receptor, cancer/apoptosis, executive function, senses, ischemia, motor function, myelination, and dependence. The results of this exploration could be in relation to the neurological symptoms of COVID-19. Furthermore, some genes from peripheral blood are already considered as biomarker of COVID-19. This method could generate new hypotheses to explore the neurological manifestations of COVID-19.

ARTERIAL HYPERTENSION FOLLOWING COVID-19: A RETROSPECTIVE STUDY OF PATIENTS IN A CENTRAL EUROPEAN TERTIARY CARE CENTER

The aim of this study was to determine the frequency of newly verified or worsened existing hypertension in patients who had coronavirus 2019 (COVID-19). To be categorized as a COVID-19 patient, a positive reverse-transcription polymerase chain reaction test at a single point in time was required. The patients’ age, history, laboratory values and antihypertensive therapy of patients were recorded. In one year, 32 of 199 patients studied had either newly verified (15) or worsened existing (17) arterial hypertension. Among those patients, the median time from a verified infection to the onset of symptoms was 3 months. When the patients were divided into groups, 4 were in the acute, 11 in the sub-acute, 8 in the chronic and 9 in the “long COVID” group. Compared to the rest of the study population, patients presenting with arterial hypertension had significantly higher systolic (median 141 mmHg vs 130 mmHg, p<0.001) and diastolic (median 93 mmHg vs 80 mmHg, p<0.001) blood pressure and were significantly younger (median 51 vs 59 years, p 0.032). Arterial hypertension following COVID-19, either newly verified or worsened existing, is a relatively common occurrence (16% of our patient pool), indicating that more effort should be directed at evaluating the blood pressure values of patients following COVID-19.

AMBULATORY BLOOD PRESSURE VARIABILITY IN YOUNG ADULTS WITH LONG-COVID SYNDROME

OBJECTIVE

The aim: To perform an overall assessment of BP and BP variability using ambulatory measurements in young adults with long COVID syndrome.

PATIENTS AND METHODS

Materials and methods: We enrolled young patients with diagnosed long-COVID syndrome (n = 58, mean age 23.07 ± 1.54 years), compared with an age-matched healthy subjects who had not suffered from COVID-19 (n = 57, mean age 22.9 ± 1.83 years). Patients with long-COVID syndrome had recovered from mild/moderate illness and none had required hospitalization. Ambulatory 24 hours blood pressure (AMBP) parameters (mean BP, daytime BP, nighttime BP, pulse pressure, nocturnal systolic BP dipping, dipper status) were measured in all participants. The variability of systolic BP (SBP) and diastolic BP (DBP) values was assessed by the following common metrics, including the average real variability (ARV), the coefficient of variation (CV), the standard deviation (SD), and the weighed SD of SBP and DBP.

RESULTS

Results: The average values of 24-hour ambulatory blood pressure, mean BP, daytime and nighttime systolic BP, diastolic BP and pulse pressure were found to be significantly different among patients with long COVID syndrome and control group. Group analyses showed that this difference was in SBP mean values (127.1 ± 6.65 mmHg and 115.93 ± 6.24 mmHg respectively) and DBP mean values (73.31 ± 5.30 mmHg and 68.79 ± 5.5 mmHg respectively) mainly at night. PP values at daytime were almost similar among groups, but PP values at nighttime were higher in patients with long-COVID syndrome (53.8 (52.44- 55.14) mmHg and 47.14 (46.45 - 47.88) mmHg respectively). Nocturnal SBP dipping was better in control group than in patients with long-COVID syndrome ( 5.3 ± 5.68 and 3.1 ± 3.79 mmHg respectively). Only 13 (22.4%) patients with long-COVID syndrome had normal dip-per status while more than half - 38 (66.7%) in healthy subjects. The values of ARV of SBP and DBP over 24-hour, awake, and asleep time frames were found to be greater in patients with long COVID syndrome than healthy controls (p < 0.05).

CONCLUSION

Conclusions: Patients with long- COVID syndrome have higher BP mean values of 24-hour ABPM particularly at nightime, significant blood pressure BP variability, which increases the risk of cardiovascular events in future. Nevertheless, the further prospective investigations is warranted to investigate the potential mechanisms and causality associations.