Long-term implications of COVID-19 on bone health: pathophysiology and therapeutics

Abstract:

Background: SARS-CoV-2 is a highly infectious respiratory virus associated with coronavirus disease (COVID-19). Discoveries in the field revealed that inflammatory conditions exert a negative impact on bone metabolism; however, only limited studies reported the consequences of SARS-CoV-2 infection on skeletal homeostasis. Inflammatory immune cells (T helper—Th17 cells and macrophages) and their signature cytokines such as interleukin (IL)-6, IL-17, and tumor necrosis factor-alpha (TNF-α) are the major contributors to the cytokine storm observed in COVID-19 disease. Our group along with others has proven that an enhanced population of both inflammatory innate (Dendritic cells—DCs, macrophages, etc.) and adaptive (Th1, Th17, etc.) immune cells, along with their signature cytokines (IL-17, TNF-α, IFN-γ, IL-6, etc.), are associated with various inflammatory bone loss conditions. Moreover, several pieces of evidence suggest that SARS-CoV-2 infects various organs of the body via angiotensin-converting enzyme 2 (ACE2) receptors including bone cells (osteoblasts—OBs and osteoclasts—OCs). This evidence thus clearly highlights both the direct and indirect impact of SARS-CoV-2 on the physiological bone remodeling process. Moreover, data from the previous SARS-CoV outbreak in 2002–2004 revealed the long-term negative impact (decreased bone mineral density—BMDs) of these infections on bone health.

Methodology: We used the keywords “immunopathogenesis of SARS-CoV-2,” “SARS-CoV-2 and bone cells,” “factors influencing bone health and COVID-19,” “GUT microbiota,” and “COVID-19 and Bone health” to integrate the topics for making this review article by searching the following electronic databases: PubMed, Google Scholar, and Scopus.

Conclusion: Current evidence and reports indicate the direct relation between SARS-CoV-2 infection and bone health and thus warrant future research in this field. It would be imperative to assess the post-COVID-19 fracture risk of SARS-CoV-2-infected individuals by simultaneously monitoring them for bone metabolism/biochemical markers. Importantly, several emerging research suggest that dysbiosis of the gut microbiota—GM (established role in inflammatory bone loss conditions) is further involved in the severity of COVID-19 disease. In the present review, we thus also highlight the importance of dietary interventions including probiotics (modulating dysbiotic GM) as an adjunct therapeutic alternative in the treatment and management of long-term consequences of COVID-19 on bone health.

Source: Sapra L, Saini C, Garg B, Gupta R, Verma B, Mishra PK, Srivastava RK. Long-term implications of COVID-19 on bone health: pathophysiology and therapeutics. Inflamm Res. 2022 Sep;71(9):1025-1040. doi: 10.1007/s00011-022-01616-9. Epub 2022 Jul 28. PMID: 35900380; PMCID: PMC9330992. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9330992/ (Full text)

The Renin-Angiotensin-System in COVID-19: Can Long COVID Be Predicted?

Abstract:

(1) Background: Co-morbidities such as hypertension and cardiovascular disease are major risk factors for severe COVID-19. The renin-angiotensin-system (RAS) is critically involved in their pathophysiology and is counterbalanced by both angiotensin-converting enzyme 2 (ACE2), the functional receptor of SARS-CoV-2, and the kallikrein-kinin-system (KKS). Considerable research interest with respect to COVID-19 treatment is, thus, currently directed towards the components of these systems. In an earlier study, we noticed significantly reduced carboxypeptidase N (CPN, KKS member) activity and partially excessive angiotensin-converting enzyme (ACE, RAS member) activity in the sera of both hospitalized (HoP) COVID-19 patients and a sub-group of covalescent patients, while in the majority of the probands recovering from the disease these values had returned to normal. The data had been obtained using bradykinin (BK) as a reporter peptide, which is a target of both CPN and ACE, and they were supplemented by serum proteomics of the same patient cohort. We hypothesized that the data could be indicative of Long COVID, which had not been fully appreciated at the time of our study.;

(2) Methods: The data were re-evaluated in the light of Long COVID. The recent literature on the RAS in COVID-19, antihypertensiva, and Long COVID was briefly reviewed.;

(3) Results: While the levels of the BK serum degradation products should return to normal concentrations during convalescence, this was not true for some patients. This could be due to persisting liver problems, because CPN is synthesized there, but also to a dysregulated RAS. This was not reflected in the levels of selected RAS/KKS serum proteins like angiotensinogen (AGT), although AGT correlated with disease severity in HoP. However, standard tests in routine patient care in Long COVID often come back normal, and it may be that BK degradation is specific in some pathophysiologies. Moreover, the HoP group was sub-divided based on the serum protein profiles and COVID-19 severity.;

(4) Conclusions: We point out two insights: 1) Sensitive technology such as omics methods might provide unexpected significant differences within the pre-defined patient groups of a clinical study. Those can only be explored, if the cohorts are large enough and properly matched with respect to the parameters known beforehand (e.g., age, gender, co-morbidities). 2) Results of the BK-reporter serum protease activity assay could be indicative of persisting liver problems and/or potentially of Long COVID. Clinical studies are required to test this hypothesis.

Source: König, S.; Vollenberg, R.; Tepasse, P. The Renin-Angiotensin-System in COVID-19: Can Long COVID Be Predicted?. Preprints.org 2023, 2023051298. https://doi.org/10.20944/preprints202305.1298.v1 (Full text available as PDF file)

Musculoskeletal involvement: COVID-19 and post COVID 19

Abstract:

The worldwide pandemic of coronavirus disease 2019 (COVID-19) was known to predominantly affect the lungs, but it was realized that COVID-19 had a large variety of clinical involvement. Cardiovascular, gastrointestinal, neurological, and musculoskeletal systems are involved by direct or indirect mechanisms with various manifestations.

The musculoskeletal involvement can manifest during COVID-19 infection, due to medications used for the treatment of COVID-19, and in the post/long COVID-19 syndrome. The major symptoms are fatigue, myalgia/arthralgia, back pain, low back pain, and chest pain. During the last two years, musculoskeletal involvement increased, but no clear consensus was obtained about the pathogenesis. However, there is valuable data that supports the hypothesis of angiotensinconverting enzyme 2, inflammation, hypoxia, and muscle catabolism. Additionally, medications that were used for treatment also have musculoskeletal adverse effects, such as corticosteroid-induced myopathy and osteoporosis. Therefore, while deciding the drugs, priorities and benefits should be taken into consideration.

Symptoms that begin three months from the onset of the COVID-19 infection, continue for at least two months, and cannot be explained by another diagnosis is accepted as post/long COVID-19 syndrome. Prior symptoms may persist and fluctuate, or new symptoms may manifest. In addition, there must be at least one symptom of infection. Most common musculoskeletal symptoms are myalgia, arthralgia, fatigue, back pain, muscle weakness, sarcopenia, impaired exercise capacity, and physical performance. In addition, the female sex, obesity, elderly patients, hospitalization, prolonged immobility, having mechanical ventilation, not having vaccination, and comorbid disorders can be accepted as clinical predictors for post/long COVID-19 syndrome.

Musculoskeletal pain is also a major problem and tends to be in chronic form. There is no consensus on the mechanism, but inflammation and angiotensin-converting enzyme 2 seem to play an important role. Localized and generalized pain may occur after COVID-19, and general pain is at least as common as localized pain. An accurate diagnosis allows physicians to initiate pain management and proper rehabilitation programs.

Source: Evcik D. Musculoskeletal involvement: COVID-19 and post COVID 19. Turk J Phys Med Rehabil. 2023 Feb 28;69(1):1-7. doi: 10.5606/tftrd.2023.12521. PMID: 37201006; PMCID: PMC10186015.

Negative correlation between ACE2 gene expression levels and loss of taste in a cohort of COVID-19 hospitalized patients: New clues to long-term cognitive disorders

Abstract:

In early 2020, one of the most prevalent symptoms of SARS-CoV-2 infection was the loss of smell (anosmia), found in 60-70% of all cases. Anosmia used to occur early, concomitantly with other symptoms, and often persisted after recovery for an extended period, sometimes for months. In addition to smell disturbance, COVID-19 has also been associated with loss of taste (ageusia). The latest research suggests that SARS-CoV-2 could spread from the respiratory system to the brain through receptors in sustentacular cells localized to the olfactory epithelium. The virus invades human cells via the obligatory receptor, angiotensin-converting enzyme II (ACE2), and a priming protease, TMPRSS2, facilitating viral penetration. There is an abundant expression of both ACE2 and TMPRSS2 in sustentacular cells.

In this study, we evaluated 102 COVID-19 hospitalized patients, of which 17.60% presented anosmia and 9.80% ageusia. ACE1ACE2, and TMPRSS2 gene expression levels in nasopharyngeal tissue were obtained by RT-qPCR and measured using ΔCT analysis. ACE1 Alu287bp association was also evaluated. Logistic regression models were generated to estimate the effects of variables on ageusia and anosmia.

Association of ACE2 expression levels with ageusia. was observed (OR: 1.35; 95% CI: 1.098-1.775); however, no association was observed between TMPRSS2 and ACE1 expression levels and ageusia. No association was observed among the three genes and anosmia, and the Alu287bp polymorphism was not associated with any of the outcomes.

Lastly, we discuss whetherthere is a bridge linking these initial symptoms, including molecular factors, to long-term COVID-19 health consequences such as cognitive dysfunctions.

Source: Braga-Paz I, Ferreira de Araújo JL, Alves HJ, de Ávila RE, Resende GG, Teixeira MM, de Aguiar RS, de Souza RP, Bahia D. Negative correlation between ACE2 gene expression levels and loss of taste in a cohort of COVID-19 hospitalized patients: New clues to long-term cognitive disorders. Front Cell Infect Microbiol. 2022 Sep 29;12:905757. doi: 10.3389/fcimb.2022.905757. PMID: 36250059; PMCID: PMC9556632. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9556632/ (Full text)

SARS-CoV-2, long COVID, prion disease and neurodegeneration

Introduction:

On the last day of the year 2019 a novel Betacoronavirus (2019-nCov), now known as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), and causing the highly transmissible and lethal pneumonia COVID-19 was first reported in Wuhan, Hubei Province in Central China (Huang et al., ; Fu et al., ; Lu and Sun, ). Since then ongoing research and long-term studies of the sequelae of SARS-CoV-2 infection have indicated that post-infection, recovery from COVID-19 and/or COVID-19 aftermath is associated with long-term physiological and neurological deficits known generically as “long COVID” (Roy et al., ; Ahmad et al., ; Baazaoui and Iqbal, ). Multiple independent epidemiological and clinical studies further indicate that SARS-CoV-2 infection and “long COVID” strongly correlate with the onset of progressive neurological disturbances that include Alzheimer’s disease (AD), prion disease (PrD) and other neurodegenerative disorders. These are apparent: (i) especially in aged and/or senile COVID-19 patients; (ii) in patients experiencing overlapping or inter-current illnesses that include heart disease, diabetes, hypertension, neuropsychiatric and other age-related neurological disorders; and (iii) in those COVID-19 patients who have experienced a particularly virulent and/or a near fatal episode of SARS-CoV-2 infection (Farheen et al., ; Flud et al., ; Fu et al., ). Conversely, increasing numbers of epidemiological studies suggest that elderly people with neurological deficits commonly observed in AD are highly vulnerable to SARS-CoV-2 infection, and especially the development of more severe forms of COVID-19 disease (Chiricosta et al., ; Hsu et al., ; Fu et al., ). The recent finding that the SARS-CoV-2 “S1” spike protein essential for viral infectivity contains prion-like domains associated with immune-evasion and the promotion of protein aggregation and aggregate “seeding” is particularly intriguing (Baazaoui and Iqbal, ; Bernardini et al., ; Tetz and Tetz, ). Based on these and other very recent findings this “Opinion” paper will: (i) address our current understanding of the emerging role of SARS-CoV-2 infection with “long COVID” with special reference to AD and PrD; (ii) will review the latest findings of the SARS-CoV-2 “S1” spike protein and its preferred interaction with the ubiquitous angiotensin converting enzyme-2 (ACE2) receptor (ACE2R); and (iii) will highlight the interplay of the molecular biology and neuropathology of SARS-CoV-2 with the unusual and immune-evasive character of prion neurobiology, AD and PrD.

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Source: Zhao Y, Jaber VR, Lukiw WJ. SARS-CoV-2, long COVID, prion disease and neurodegeneration. Front Neurosci. 2022 Sep 27;16:1002770. doi: 10.3389/fnins.2022.1002770. PMID: 36238082; PMCID: PMC9551214.  Zhao Y, Jaber VR, Lukiw WJ. SARS-CoV-2, long COVID, prion disease and neurodegeneration. Front Neurosci. 2022 Sep 27;16:1002770. doi: 10.3389/fnins.2022.1002770. PMID: 36238082; PMCID: PMC9551214. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9551214/ (Full text)