Tag: lung function

Persistent alveolar type 2 dysfunction and lung structural derangement in post-acute COVID-19

Abstract:

SARS-CoV-2 infection can manifest as a wide range of respiratory and systemic symptoms well after the acute phase of infection in over 50% of patients. Key questions remain on the long-term effects of infection on tissue pathology in recovered COVID-19 patients. To address these questions we performed multiplexed imaging of post-mortem lung tissue from 12 individuals who died post-acute COVID-19 (PC) and compare them to lung tissue from patients who died during the acute phase of COVID-19, or patients who died with idiopathic pulmonary fibrosis (IPF), and otherwise healthy lung tissue.

We find evidence of viral presence in the lung up to 359 days after the acute phase of disease, including in patients with negative nasopharyngeal swab tests. The lung of PC patients are characterized by the accumulation of senescent alveolar type 2 cells, fibrosis with hypervascularization of peribronchial areas and alveolar septa, as the most pronounced pathophysiological features. At the cellular level, lung disease of PC patients, while distinct, shares pathological features with the chronic pulmonary disease of IPF. which may help rationalize interventions for PC patients.

Altogether, this study provides an important foundation for the understanding of the long-term effects of SARS-CoV-2 pulmonary infection at the microanatomical, cellular, and molecular level.

Source: André F. Rendeiro, Hiranmayi Ravichandran, Junbum Kim, Alain C. Borczuk, Olivier Elemento, Robert E. Schwartz. Persistent alveolar type 2 dysfunction and lung structural derangement in post-acute COVID-19. medRxiv 2022.11.28.22282811; doi: https://doi.org/10.1101/2022.11.28.22282811 https://www.medrxiv.org/content/10.1101/2022.11.28.22282811v1.full-text  (Full text)

The Investigation of Pulmonary Abnormalities using Hyperpolarised Xenon Magnetic Resonance Imaging in Patients with Long-COVID

Abstract:

Background: Long-COVID is an umbrella term used to describe ongoing symptoms following COVID-19 infection after four weeks. Symptoms are wide-ranging but breathlessness is one of the most common and can persist for months after the initial infection. Investigations including Computed Tomography (CT), and physiological measurements (lung function tests) are usually unremarkable. The mechanisms driving breathlessness remain unclear, and this may be hindering the development of effective treatments.

Methods: Eleven non-hospitalised Long-COVID (NHLC, 4 male), 12 post-hospitalised COVID-19 (PHC, 10 male) patients were recruited from a Post-COVID Assessment clinic, and thirteen healthy controls (6 female) were recruited to undergo Hyperpolarized Xenon Magnetic Resonance Imaging (Hp-XeMRI). NHLC and PHC participants underwent contemporaneous CT, Hp-XeMRI, lung function tests, 1-minute sit-to-stand test and breathlessness questionnaires. Statistical analysis included group and pair-wise comparisons between patients and controls, and correlations between patient clinical and imaging data.

Results: NHLC and PHC patients were 287 ± 79 [range 190-437] and 149 ± 68 [range 68-269] days from infection, respectively. All NHLC patients had normal CT scans, and the PHC had normal or near normal CT scans (0.3/25 ± 0.6 [range 0-2] and 7/25 ± 5 [range 4-8], respectively). There was a significant difference in TLco (%) between NHLC and PHC patients (76 ± 8 % vs 86 ± 8%, respectively, p = 0.04) but no differences in other measurements of lung function. There were significant differences in RBC:TP mean between volunteers (0.45 ± 0.07, range [0.33-0.55]) and PHC (0.31 ± 0.11, [range 0.16-0.37]) and NHLC (0.35 ± 0.09, [range 0.26-0.58]) patients, but not between NHLC and PHC (p = 0.26).

Conclusion: There are RBC:TP abnormalities in NHLC and PHC patients, with NHLC patients also demonstrating lower TLco than PHC patients despite their having normal CT scans. These abnormalities are present many months after the initial infection.

Summary statement: Hyperpolarized Xenon MRI and TLco demonstrate significantly impaired gas transfer in non-hospitalised long-COVID patients when all other investigations are normal.

Source:  James T. Grist, Guilhem J. Collier, Huw Walters, Mitchell Chen, Gabriele Abu Eid, Aviana Laws, Violet Matthews, Kenneth Jacob, Susan Cross, Alexandra Eves, Marianne Durant, Anthony Mcintyre, Roger Thompson, Rolf F. Schulte, Betty Raman, Peter A. Robbins, Jim M. Wild, Emily Fraser, Fergus Gleeson. The Investigation of Pulmonary Abnormalities using Hyperpolarised Xenon Magnetic Resonance Imaging in Patients with Long-COVID.
medRxiv 2022.02.01.22269999; doi: https://doi.org/10.1101/2022.02.01.22269999