Increase in gut permeability and oxidized ldl is associated with post-acute sequelae of SARS-CoV-2

Synergy Between NK Cells and Monocytes in Potentiating Cardiovascular Disease Risk in Severe COVID-19

BACKGROUND

Evidence suggests that COVID-19 predisposes to cardiovascular diseases (CVDs). While monocytes/macrophages play a central role in the immunopathogenesis of atherosclerosis, less is known about their immunopathogenic mechanisms that lead to CVDs during COVID-19. Natural killer (NK) cells, which play an intermediary role during pathologies like atherosclerosis, are dysregulated during COVID-19. Here, we sought to investigate altered immune cells and their associations with CVD risk during severe COVID-19.

METHODS

We measured plasma biomarkers of CVDs and determined phenotypes of circulating immune subsets using spectral flow cytometry. We compared these between patients with severe COVID-19 (severe, n=31), those who recovered from severe COVID-19 (recovered, n=29), and SARS-CoV-2-uninfected controls (controls, n=17). In vivo observations were supported using in vitro assays to highlight possible mechanistic links between dysregulated immune subsets and biomarkers during and after COVID-19. We performed multidimensional analyses of published single-cell transcriptome data of monocytes and NK cells during severe COVID-19 to substantiate in vivo findings.

RESULTS

During severe COVID-19, we observed alterations in cardiometabolic biomarkers including oxidized-low-density lipoprotein, which showed decreased levels in severe and recovered groups. Severe patients exhibited dysregulated monocyte subsets, including increased frequencies of proinflammatory intermediate monocytes (also observed in the recovered) and decreased nonclassical monocytes. All identified NK-cell subsets in the severe COVID-19 group displayed increased expression of activation and tissue-resident markers, such as CD69 (cluster of differentiation 69). We observed significant correlations between altered immune subsets and plasma oxidized-low-density lipoprotein levels. In vitro assays revealed increased uptake of oxidized-low-density lipoprotein into monocyte-derived macrophages in the presence of NK cells activated by plasma of patients with severe COVID-19. Transcriptome analyses confirmed enriched proinflammatory responses and lipid dysregulation associated with epigenetic modifications in monocytes and NK cells during severe COVID-19.

CONCLUSIONS

Our study provides new insights into the involvement of monocytes and NK cells in the increased CVD risk observed during and after COVID-19.

COVID-19 in Pediatric Populations

The COVID-19 pandemic reshaped the landscape of respiratory viral illnesses, causing common viruses to fade as SARS-CoV-2 took precedence. By 2023, more than 96% of the children in the United States were estimated to have been infected with SARS-CoV-2, with certain genetic predispositions and underlying health conditions posing risk factors for severe disease in children. Children, in general though, exhibit immunity advantages, protecting against aspects of the SARS-CoV-2 infection known to drive increased severity in older adults. Post-COVID-19 complications such as multisystem inflammatory syndrome in children and long COVID have emerged, underscoring the importance of vaccination. Here, we highlight the risks of severe pediatric COVID-19, age-specific immunoprotection, comparisons of SARS-CoV-2 with other respiratory viruses, and factors contributing to post-COVID-19 complications in children.

The Spectrum of Postacute Sequelae of COVID-19 in Children: From MIS-C to Long COVID

The effects of SARS-CoV-2 infection on children continue to evolve following the onset of the COVID-19 pandemic. Although life-threatening multisystem inflammatory syndrome in children (MIS-C) has become rare, long-standing symptoms stemming from persistent immune activation beyond the resolution of acute SARS-CoV-2 infection contribute to major health sequelae and continue to pose an economic burden. Shared pathophysiologic mechanisms place MIS-C and long COVID within a vast spectrum of postinfectious conditions characterized by intestinal dysbiosis, increased gut permeability, and varying degrees of immune dysregulation. Insights obtained from MIS-C will help shape our understanding of the more indolent and prevalent postacute sequelae of COVID and ultimately guide efforts to improve diagnosis and management of postinfectious complications of SARS-CoV-2 infection in children.

Sex Modifies the Effect of COVID-19 on Arterial Elasticity

There is limited long-term evidence on the effects of COVID-19 on vascular injury between male and female sex. An adult cohort of COVID-19 survivors (COVID+) and confirmed SARS-CoV-2 antibody-negative participants (COVID-) were prospectively enrolled. COVID+ participants who have documented the presence of persistent symptoms four weeks following infection were considered to have post-acute sequelae of COVID-19 (PASC). Non-invasive, FDA-approved EndoPAT (Endo-PAT2000) was used for endothelial assessment. COVID-(n = 94) were 1:1 propensity score matched to COVID+ (n = 151) on baseline covariates including sex. Among COVID+, 66.2% (n = 100) had PASC. Higher levels of coagulation marker, D-dimer (p = 0.001), and gut permeability marker, zonulin (p = 0.001), were associated with female sex. Estimated differences in augmentation index (AI) between COVID- (0.9 ± 17.2) and COVID+ (8.4 ± 15.7; p = 0.001) and between female and male sex (12.9 ± 1.9; p < .0001) were observed. Among COVID+ with PASC, the average AI (10.5 ± 1.6) was 9.7 units higher than COVID- (p < .0001) and 6.2 units higher compared to COVID+ with no PASC (p = 0.03). COVID+ PASC+ female sex had the highest AI (14.3 ± 1.9). The effects of SARS-CoV-2 infection on vascular function varies across strata of sex and female sex in the post-acute phase of COVID-19 have the worse arterial elasticity (highest AI).

The Long-Term Effect of COVID-19 Infection on Body Composition

BACKGROUND

The effect of COVID-19 infection versus the indirect effect of the pandemic on body composition remains unclear. This study investigates the long-term changes in body composition in COVID-19 survivors compared to a contemporary control group.

METHOD

This is a prospective study involving adults who underwent a pre-pandemic whole-body DXA scan (DXA#1) between 2017 and 2019. Participants were asked to return for a repeat whole-body DXA scan (DXA#2) after the pandemic. Detailed data were collected including their medical and COVID-19 history. Inflammation markers and fasting lipids were measured. For those participants who experienced a COVID-19 infection between the two DXAs, DXA#2 was acquired at least one year after COVID-19 infection.

RESULTS

Overall, 160 adults were enrolled; 32.5% females, 51.8% non-white, with mean age of 43.2 years. Half (n = 80) of the participants experienced a COVID-19 infection between their two DXA scans (COVID-19+ group), and the other half had never had COVID-19. COVID-19-negative participants displayed an increase in annualized trunk fat (g) [922.5 vs. 159.7; p = 0.01], total fat (g) [1564.3 vs. 199.9; p = 0.2], and LBM (g) [974.9 vs. -64.5; p = 0.0002] when compared to the COVID-19+ group. However, among the COVID-19+ group, no differences were seen in annualized trunk fat, total fat mass, or LBM between those with PASC and without (p > 0.05).

CONCLUSION

During the pandemic, both the COVID-19 survivors and the COVID-19-negative group exhibited increases in weight, total fat, and trunk fat, likely associated with pandemic-linked lifestyle modifications. However, only COVID-19 survivors displayed a decline in lean body mass over the same period, regardless of PASC symptoms.

The Multisystem Impact of Long COVID: A Comprehensive Review

(1) Background: COVID-19 was responsible for the latest pandemic, shaking and reshaping healthcare systems worldwide. Its late clinical manifestations make it linger in medical memory as a debilitating illness over extended periods. (2) Methods: the recent literature was systematically analyzed to categorize and examine the symptomatology and pathophysiology of Long COVID across various bodily systems, including pulmonary, cardiovascular, gastrointestinal, neuropsychiatric, dermatological, renal, hematological, and endocrinological aspects. (3) Results: The review outlines the diverse clinical manifestations of Long COVID across multiple systems, emphasizing its complexity and challenges in diagnosis and treatment. Factors such as pre-existing conditions, initial COVID-19 severity, vaccination status, gender, and age were identified as influential in the manifestation and persistence of Long COVID symptoms. This condition is highlighted as a debilitating disease capable of enduring over an extended period and presenting new symptoms over time. (4) Conclusions: Long COVID emerges as a condition with intricate multi-systemic involvement, complicating its diagnosis and treatment. The findings underscore the necessity for a nuanced understanding of its diverse manifestations to effectively manage and address the evolving nature of this condition over time.

Arterial Stiffness and Oxidized LDL Independently Associated With Post-Acute Sequalae of SARS-CoV-2

OBJECTIVE

COVID-19 survivors can experience lingering symptoms known as post-acute sequelae of SARS-CoV-2 (PASC) that appear in different phenotypes, and its etiology remains elusive. We assessed the relationship of endothelial dysfunction with having COVID and PASC.

METHODS

Data was collected from a prospectively enrolled cohort (n=379) of COVID-negative and COVID-positive participants with and without PASC. Primary outcomes, endothelial function (measured by reactive hyperemic index [RHI]), and arterial elasticity (measured by augmentation index standardized at 75 bpm [AI]), were measured using the FDA approved EndoPAT. Patient characteristics, labs, metabolic measures, markers of inflammation, and oxidized LDL (ox-LDL) were collected at each study visit, and PASC symptoms were categorized into 3 non-exclusive phenotypes: cardiopulmonary, neurocognitive, and general. COVID-negative controls were propensity score matched to COVID-negative-infected cases using the greedy nearest neighbor method.

RESULTS

There were 14.3% of participants who were fully recovered COVID positive and 28.5% who were COVID positive with PASC, averaging 8.64 ± 6.26 total number of symptoms. The mean RHI was similar across the cohort and having COVID or PASC was not associated with endothelial function (P=0.33). Age (P<0.0001), female sex (P<0.0001), and CRP P=0.04) were positively associated with arterial stiffness, and COVID positive PASC positive with neurological and/or cardiopulmonary phenotypes had the worst arterial elasticity (highest AI). Values for AI (P=0.002) and ox-LDL (P<0.0001) were independently and positively associated with an increased likelihood of having PASC.

CONCLUSION

There is evidence of an independent association between PASC, ox-LDL, and arterial stiffness with neurological and/or cardiopulmonary phenotypes having the worst arterial elasticity. Future studies should continue investigating the role of oxidative stress in the pathophysiology of PASC.

Synergistic Role of NK Cells and Monocytes in Promoting Atherogenesis in Severe COVID-19 Patients

Clinical data demonstrate an increased predisposition to cardiovascular disease (CVD) following severe COVID-19 infection. This may be driven by a dysregulated immune response associated with severe disease. Monocytes and vascular tissue resident macrophages play a critical role in atherosclerosis, the main pathology leading to ischemic CVD. Natural killer (NK) cells are a heterogenous group of cells that are critical during viral pathogenesis and are known to be dysregulated during severe COVID-19 infection. Their role in atherosclerotic cardiovascular disease has recently been described. However, the contribution of their altered phenotypes to atherogenesis following severe COVID-19 infection is unknown. We demonstrate for the first time that during and after severe COVID-19, circulating proinflammatory monocytes and activated NK cells act synergistically to increase uptake of oxidized low-density lipoprotein (Ox-LDL) into vascular tissue with subsequent foam cell generation leading to atherogenesis despite recovery from acute infection. Our data provide new insights, revealing the roles of monocytes/macrophages, and NK cells in COVID-19-related atherogenesis.