Endothelial dysfunction in COVID-19: an overview of evidence, biomarkers, mechanisms and potential therapies

Abstract:

The fight against coronavirus disease 2019 (COVID-19) caused by SARS-CoV-2 infection is still raging. However, the pathophysiology of acute and post-acute manifestations of COVID-19 (long COVID-19) is understudied. Endothelial cells are sentinels lining the innermost layer of blood vessel that gatekeep micro- and macro-vascular health by sensing pathogen/danger signals and secreting vasoactive molecules. SARS-CoV-2 infection primarily affects the pulmonary system, but accumulating evidence suggests that it also affects the pan-vasculature in the extrapulmonary systems by directly (via virus infection) or indirectly (via cytokine storm), causing endothelial dysfunction (endotheliitis, endothelialitis and endotheliopathy) and multi-organ injury.

Mounting evidence suggests that SARS-CoV-2 infection leads to multiple instances of endothelial dysfunction, including reduced nitric oxide (NO) bioavailability, oxidative stress, endothelial injury, glycocalyx/barrier disruption, hyperpermeability, inflammation/leukocyte adhesion, senescence, endothelial-to-mesenchymal transition (EndoMT), hypercoagulability, thrombosis and many others. Thus, COVID-19 is deemed as a (micro)vascular and endothelial disease. Of translational relevance, several candidate drugs which are endothelial protective have been shown to improve clinical manifestations of COVID-19 patients.

The purpose of this review is to provide a latest summary of biomarkers associated with endothelial cell activation in COVID-19 and offer mechanistic insights into the molecular basis of endothelial activation/dysfunction in macro- and micro-vasculature of COVID-19 patients. We envisage further development of cellular models and suitable animal models mimicking endothelial dysfunction aspect of COVID-19 being able to accelerate the discovery of new drugs targeting endothelial dysfunction in pan-vasculature from COVID-19 patients.

Source: Xu, Sw., Ilyas, I. & Weng, Jp. Endothelial dysfunction in COVID-19: an overview of evidence, biomarkers, mechanisms and potential therapies. Acta Pharmacol Sin (2022). https://doi.org/10.1038/s41401-022-00998-0 https://www.nature.com/articles/s41401-022-00998-0 (Full text)

New‑onset neuropsychiatric sequelae and ‘long‑COVID’ syndrome (Review)

Abstract:

The ongoing coronavirus disease 2019 (COVID‑19) pandemic has had a widespread impact on individuals’ mental health through indirect psychological and social mechanisms, related to factors such as fear of infection or death, social isolation, lack of social support and financial instability.
The severe acute respiratory syndrome coronavirus 2 (SARS‑CoV‑2) infection has also been associated with the development or recurrence of neuropsychiatric symptoms, both during the acute phase, as well as during the post‑acute ‘long‑COVID’ phase. In addition to the COVID‑19 survivors with a mental health history that are at a high risk of experiencing a range of neuropsychiatric symptoms following resolution of acute COVID‑19, there is accumulating evidence that a diagnosis of COVID‑19 may also be associated with new‑onset neuropsychiatric morbidity among survivors without pre‑existing mental health disorders.
In particular, studies investigating the incidence of post‑acute neuropsychiatric sequelae, based mostly on retrospective cohort study designs and data from national health registries, have reported the development of new‑onset manifestations, including depression, anxiety, psychotic symptoms, sleep disturbances and fatigue. Nevertheless, when COVID‑19 survivors were compared with SARS‑CoV‑2‑negative controls and especially survivors of other disorders (such as influenza), the findings regarding the risk of incident neuropsychiatric manifestations varied among studies.
While there is evidence of an association between SARS‑CoV‑2 infection and the subsequent occurrence of new‑onset neuropsychiatric symptoms, especially among patients with increased disease severity, further research using methodological approaches less susceptible to confounding bias is required to establish causal relationships.
Source: Efstathiou, V., Stefanou, M., Demetriou, M., Siafakas, N., Katsantoni, E., Makris, M., Tsivgoulis, G., Zoumpourlis, V., Kympouropoulos, S. P., Tsoporis, J. N., Spandidos, D. A., Ferentinos, P., Smyrnis, N., Rizos, E.”New‑onset neuropsychiatric sequelae and ‘long‑COVID’ syndrome (Review)”. Experimental and Therapeutic Medicine 24.5 (2022): 705. https://www.spandidos-publications.com/10.3892/etm.2022.11641 (Full text available as PDF file)

Post-Viral Fatigue in COVID-19: A Review of Symptom Assessment Methods, Mental, Cognitive, and Physical Impairment

Abstract:

Coronavirus 2 is responsible for Severe Acute Respiratory Syndrome-Coronavirus-2 (SARS-CoV-2), and the main sequela is persistent fatigue. Post-viral fatigue is common and affects patients with mild, asymptomatic coronavirus disease-2019 (COVID-19). However, the exact mechanisms involved in developing post-COVID-19 fatigue remain unclear. Furthermore, physical and cognitive impairments in these individuals have been widely described. Therefore, this review aims to summarize and propose tools from a multifaceted perspective to assess COVID-19 infection.

Herein, we point out the instruments that can be used to assess fatigue in long-term COVID-19: fatigue in a subjective manner or fatigability in an objective manner. For physical and mental fatigue, structured questionnaires were used to assess perceived symptoms, and physical and cognitive performance assessment tests were used to measure fatigability using reduced performance.

Source: Campos MC, Nery T, Starke AC, de Bem Alves AC, Speck AE, Junior ASA. Post-Viral Fatigue in COVID-19: A Review of Symptom Assessment Methods, Mental, Cognitive, and Physical Impairment. Neurosci Biobehav Rev. 2022 Oct 3:104902. doi: 10.1016/j.neubiorev.2022.104902. Epub ahead of print. PMID: 36202253; PMCID: PMC9528075. https://www.sciencedirect.com/science/article/pii/S0149763422003918 (Full text)

Long-COVID Syndrome and the Cardiovascular System: A Review of Neurocardiologic Effects on Multiple Systems

Abstract:

Purpose of review: Long-COVID syndrome is a multi-organ disorder that persists beyond 12 weeks post-acute SARS-CoV-2 infection (COVID-19). Here, we provide a definition for this syndrome and discuss neuro-cardiology involvement due to the effects of (1) angiotensin-converting enzyme 2 receptors (the entry points for the virus), (2) inflammation, and (3) oxidative stress (the resultant effects of the virus).

Recent findings: These effects may produce a spectrum of cardio-neuro effects (e.g., myocardial injury, primary arrhythmia, and cardiac symptoms due to autonomic dysfunction) which may affect all systems of the body. We discuss the symptoms and suggest therapies that target the underlying autonomic dysfunction to relieve the symptoms rather than merely treating symptoms. In addition to treating the autonomic dysfunction, the therapy also treats chronic inflammation and oxidative stress. Together with a full noninvasive cardiac workup, a full assessment of the autonomic nervous system, specifying parasympathetic and sympathetic (P&S) activity, both at rest and in response to challenges, is recommended. Cardiac symptoms must be treated directly. Cardiac treatment is often facilitated by treating the P&S dysfunction. Cardiac symptoms of dyspnea, chest pain, and palpitations, for example, need to be assessed objectively to differentiate cardiac from neural (autonomic) etiology. Long-term myocardial injury commonly involves P&S dysfunction. P&S assessment usually connects symptoms of Long-COVID to the documented autonomic dysfunction(s).

Source: DePace NL, Colombo J. Long-COVID Syndrome and the Cardiovascular System: A Review of Neurocardiologic Effects on Multiple Systems. Curr Cardiol Rep. 2022 Sep 30:1–16. doi: 10.1007/s11886-022-01786-2. Epub ahead of print. PMID: 36178611; PMCID: PMC9524329.  https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9524329/ (Full text)

The Neurobiology of Long COVID

Abstract:

Persistent neurological and neuropsychiatric symptoms affect a substantial fraction of people after COVID-19 and represent a major component of the post-acute COVID syndrome, also known as long COVID. Here, we review what is understood about the pathobiology of post-acute COVID-19 impacts on the CNS and discuss possible neurobiological underpinnings of the cognitive symptoms affecting COVID-19 survivors. We propose the chief mechanisms that may contribute to this emerging neurological health crisis.
Source: Michelle Monje, Akiko Iwasaki. The Neurobiology of Long COVID. Published:October 06, 2022. DOI: https://doi.org/10.1016/j.neuron.2022.10.006 https://www.cell.com/neuron/pdf/S0896-6273(22)00910-2.pdf (Full text available as PDF file)

Gut Microbiota Dynamics in Relation to Long-COVID-19 Syndrome: Role of Probiotics to Combat Psychiatric Complications

Increasing numbers of patients who recover from COVID-19 report lasting symptoms, such as fatigue, muscle weakness, dementia, and insomnia, known collectively as post-acute COVID syndrome or long COVID. These lasting symptoms have been examined in different studies and found to influence multiple organs, sometimes resulting in life-threating conditions.
In this review, these symptoms are discussed in connection to the COVID-19 and long-COVID-19 immune changes, highlighting oral and psychiatric health, as this work focuses on the gut microbiota’s link to long-COVID-19 manifestations in the liver, heart, kidney, brain, and spleen. A model of this is presented to show the biological and clinical implications of gut microbiota in SARS-CoV-2 infection and how they could possibly affect the therapeutic aspects of the disease. Probiotics can support the body’s systems in fighting viral infections. This review focuses on current knowledge about the use of probiotics as adjuvant therapies for COVID-19 patients that might help to prevent long-COVID-19 complications.
Source: Alenazy MF, Aljohar HI, Alruwaili AR, Daghestani MH, Alonazi MA, Labban RS, El-Ansary AK, Balto HA. Gut Microbiota Dynamics in Relation to Long-COVID-19 Syndrome: Role of Probiotics to Combat Psychiatric Complications. Metabolites. 2022; 12(10):912. https://doi.org/10.3390/metabo12100912 (Full text)

Rehabilitation in long COVID-19: A mini-review

Abstract:

We have been experiencing multiple waves of the coronavirus disease 2019 (COVID-19) pandemic. With these unprecedented waves, we have entered into an era of ‘new normal’. This pandemic has enforced us to rethink the very basics of childhood learning: Habits, health etiquette, and hygiene. Rehabilitation has immense importance during this pandemic considering a few aspects. Multidisciplinary COVID-19 rehabilitation clinics are essential to address the demand. The equitable distribution of COVID-19 rehabilitation services for differently-abled individuals during the pandemic is an important aspect. Rehabilitation needs identification and further studies on various rehabilitation interventions are among the key unmet future research needs.

Source: Swarnakar R, Yadav SL. Rehabilitation in long COVID-19: A mini-review. World J Methodol. 2022 Jul 20;12(4):235-245. doi: 10.5662/wjm.v12.i4.235. PMID: 36159093; PMCID: PMC9350732. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9350732/ (Full text)

Neurological post-acute sequelae of SARS-CoV-2 infection (PASC)

Abstract:

The novel corona virus infectious disease, COVID-19, caused by SARS-CoV-2, can have two phases: acute (generally 4 weeks after onset) and chronic (> 4 weeks after onset). Both phases include a wide variety of signs and symptoms including neurological and psychiatric symptoms. The signs and symptoms that are considered sequelae of COVID-19 are termed post-COVID condition, long COVID-19, and post-acute sequelae of SARS-CoV-2 infection (PASC).

PASC symptoms include fatigue, dyspnea, palpitation, dysosmia, sub-fever, hypertension, alopecia, sleep problems, loss of concentration, amnesia, numbness, pain, gastrointestinal symptoms, depression, and anxiety. Because the specific pathophysiology of PASC has not yet been clarified, there are no definite criteria of the condition, hence the World Health Organization’s definition is quite broad. Consequently, it is difficult to correctly diagnose PASC.

Approximately 50% of patients may show at least one PASC symptom up to 12 months after COVID-19 infection; however, the exact prevalence of PASC has not been determined. Despite extensive research in progress worldwide, there are currently no clear diagnostic methodologies or treatments for PASC.

In this review, we discuss the currently available information on PASC and highlight the neurological sequelae of COVID-19 infection. Furthermore, we provide clinical suggestions for diagnosing and caring for PASC patients based on our outpatient clinic experience.

Source: Takao M, Ohira M. Neurological post-acute sequelae of SARS-CoV-2 infection (PASC). Psychiatry Clin Neurosci. 2022 Sep 23. doi: 10.1111/pcn.13481. Epub ahead of print. PMID: 36148558. https://pubmed.ncbi.nlm.nih.gov/36148558/

COVID-19 immunopathology: From acute diseases to chronic sequelae

Abstract:

The clinical manifestation of coronavirus disease 2019 (COVID-19) mainly targets the lung as a primary affected organ, which is also a critical site of immune cell activation by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). However, recent reports also suggest the involvement of extrapulmonary tissues in COVID-19 pathology.

The interplay of both innate and adaptive immune responses is key to COVID-19 management. As a result, a robust innate immune response provides the first line of defense, concomitantly, adaptive immunity neutralizes the infection and builds memory for long-term protection. However, dysregulated immunity, both innate and adaptive, can skew towards immunopathology both in acute and chronic cases.

Here we have summarized some of the recent findings that provide critical insight into the immunopathology caused by SARS-CoV-2, in acute and post-acute cases. Finally, we further discuss some of the immunomodulatory drugs in preclinical and clinical trials for dampening the immunopathology caused by COVID-19.

Source: Arish M, Qian W, Narasimhan H, Sun J. COVID-19 immunopathology: From acute diseases to chronic sequelae. J Med Virol. 2022 Sep 3. doi: 10.1002/jmv.28122. Epub ahead of print. PMID: 36056655. https://onlinelibrary.wiley.com/doi/10.1002/jmv.28122 (Full text)

Memory alterations after COVID-19 infection: a systematic review

Abstract:

SARS-CoV-2 infection has a wide range of both acute and long-term symptoms. Memory alterations have been frequently reported in studies that explore cognition. The main objective of the systematic review is to update and further analyze the existing evidence of objective memory impairments in long-COVID-19 considering sample and study design characteristics, as well as to explore associations between memory performance and their epidemiological, clinical, and pathological features.

A total of 13 studies were identified by searching in PubMed, Web of Science, and PsycInfo databases up to May 6, 2022. Most studies evaluated verbal component of memory in the short-term and long-term recall up to 30 min and mainly performed a single assessment completed at 4-6 months after the infection. The samples mainly consisted of middle-aged adults that required hospitalization. Samples were not stratified by sex, age, and severity.

Poor verbal learning was reported in most cases (6-58%), followed by deficits in long-term (4-58%) and short-term (4-37%) verbal memory. Visuospatial component of memory was studied less than verbal component, showing impairment of long-term retention of visual items (10-49%). COVID-19 severity in the acute stage was not systematically associated with poor memory performance. Verbal memory deficits were associated with anxiety and depression.

The existing literature on objective memory assessment in long-COVID suggests further research is warranted to confirm memory dysfunction in association with epidemiological, pathological, and clinical factors, using both verbal and visuospatial tests, and exploring in deep long-term memory deficits.

Source: Llana T, Zorzo C, Mendez-Lopez M, Mendez M. Memory alterations after COVID-19 infection: a systematic review. Appl Neuropsychol Adult. 2022 Sep 15:1-14. doi: 10.1080/23279095.2022.2123739. Epub ahead of print. PMID: 36108666.  https://pubmed.ncbi.nlm.nih.gov/36108666/