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Introduction: The role of mitochondria in post coronavirus disease 2019 (post-COVID-19) complications is unclear, especially in the long-term pulmonary complications. This study aims to investigate the association between post-COVID-19 pulmonary complications and mitochondrial regulatory proteins in the context of oxidative stress. Methodology: Patients who had recovered from COVID-19 were enrolled. According to the evidence of persistent interstitial lung lesions on computed tomography (CT), patients were divided into a long-term pulmonary complications group (P(+)) and a control group without long-term pulmonary complications (P(−)). We randomly selected 80 patients for investigation (40 subjects for each group). Biomarkers levels were determined by enzyme-linked immunosorbent assay (ELISA). Results: The serum concentrations of mitochondrial regulatory proteins were significantly higher in the P(+) group, including PTEN-induced kinase 1 (PINK1): 1.62 [1.02–2.29] ng/mL vs. 1.34 [0.94–1.74] ng/mL (p = 0.046); Dynamin-1-like protein (DNM1L): 1.6 [0.9–2.4] ng/mL IQR vs. 0.9 [0.5–1.6] ng/mL (p = 0.004); and Mitofusin-2 (MFN2): 0.3 [0.2–0.5] ng/mL vs. 0.2 [0.1–0.3] ng/mL IQR (p = 0.001). Patients from the P(+) group also had higher serum levels of chemokine ligand 18 (PARC, CCL18), IL-6, and tumour necrosis factor-alpha (TNF-α) cytokines than the P(−) group. The concentration of interferon alpha (IFN-α) was decreased in the P(+) group. Furthermore, we observed statistically significant correlations between the advanced glycation end product (sRAGE) and TNF-α (Pearson’s factor R = 0.637; p < 0.001) and between serum levels of DNM1L and IFN-α (Pearson’s factor R = 0.501; p = 0.002) in P(+) patients. Conclusions: Elevated concentrations of mitochondrial biomarkers in post-COVID-19 patients with long-term pulmonary complications indicate their possible role in the pathobiology of COVID-19 pulmonary sequelae. Oxidative stress is associated with the immune response and inflammation after COVID-19. TNF-α could be a promising biomarker for predicting pulmonary complications and may be a potential target for therapeutic intervention in patients with post-COVID-19 complications.

1. Introduction: Despite growing knowledge about transmission and relatively wide access to prophylaxis, the world is still facing a severe acute respiratory syndrome coronavirus 2 (SARS CoV 2) global pandemic. Under these circumstances telemedicine emerges as a powerful tool for safe at-home surveillance after a hospital discharge; the data on when to safely release a patient after acute COVID 19 is scarce. Reckoning an urgent need for improving outpatient management and possibly fatal complications of the post-COVID period, we performed the pilot telemonitoring program described below.2. Materials and methods: Patients were involved in the study between December 2020 and May 2021. Recruitment was performed either during the hospital discharge (those hospitalized in a Barlicki Memorial Hospital in Lodz) or first outpatient visit up to 6 weeks after discharge from another center. Every participant received equipment for daily saturation and heart rate measurement coupled with a tablet for remote data transmission. The measurements were made after at least fifteen minutes of rest in a sitting position without oxygen supplementation. Along with the measurements, the cough and dyspnea daily surveys (1 to 5 points) and Fatigue Assessment Scale weekly surveys were filled. We expected a drop of saturation during thromboembolic events, infectious complications, etc.3. Results: A total of 30 patients were monitored for a minimum period of 45 days, at least 2 weeks after spontaneous saturation normalization. Mean age was 55 (mean 55.23; SD +/- 10.64 years). The group was divided according to clinical improvement defined as the ≥10% functional vital capacity (FVC) raise or ≥15% lung transfer for carbon monoxide (TL,CO) rise. Our findings suggest that at-rest home saturation measurements below 94% (p=0.03) correspond with the lack of clinical improvement in post-COVID observation (p=0.03). The non-improvement group presented with lower mean – 94 (93-96) % vs 96 (95-97)%, p=0.01 and minimum saturation – 89 (86-92)% vs. 92 (90-94)%, p=0.04. They also presented higher variations in saturation measurements; saturation amplitude was 9 (7-11)% vs 7 (4-8)%, p=0.03; up to day 22 most of the saturation differences reached statistical significance. Last but not least, we discovered that participants missing 2 or more measurements during the observation were more often ranked into the clinical improvement group (p=0.01). Heart rate day-to-day measurements did not differ between both groups; gathered data about dyspnea and cough intensity did not reach statistical significance either. 4. Conclusions: A better understanding of the disease’s natural history will ultimately lead us to a better understanding of long COVID symptoms and corresponding threats. In this paper, we have found home oxygen saturation telemonitoring to be useful in the prediction of the trajectory of the disease course. Our findings suggest that detection of at-rest home saturation measurement equal to or below 94% corresponds with the lack of clinical improvement in the time of observation and this group of patients presented higher variability of day-to-day oxygen saturation measurements. The determination of which patient should be involved in telemedicine programs after discharge requests further research.

(1) Introduction: The role of soluble integrins in post-COVID-19 complications is unclear, especially in long-term pulmonary lesions. The purpose of this study was to investigate the association between soluble ITGa2, ITGaM and ITGb2 integrin subunits and long COVID-19 pulmonary complications. (2) Methodology: Post-COVID-19 patients were enrolled. According to the evidence of persistent interstitial lung lesions on CT, patients were divided into a long-term pulmonary complications group (P(+)) and a control group without long-term pulmonary complications (P(−)). We randomly selected 80 patients for further investigation (40 subjects for each group). Levels of ITGa2, ITGaM and ITGb2 integrin subunits were determined by ELISA assay. (3) Results: The serum concentration of sITGaM and sITGb2 were significantly higher in the P(+) group (sITGaM 18.63 ng/mL [IQR 14.17–28.83] vs. 14.75 ng/mL [IQR 10.91–20] p = 0.01 and sITGb2 10.55 ng/mL [IQR 6.53–15.83] vs. 6.34 ng/mL [IQR 4.98-9.68] p = 0.002). We observed a statistically significant correlation between sITGaM and sITGb2 elevation in the P(+) group (R = 0.42; p = 0.01). Patients from the P(+) group had a lower (1.82 +/−0.84 G/L) lymphocyte level than the P(−)group (2.28 +/−0.79 G/L), p = 0.03. Furthermore, we observed an inverse correlation in the P(−) group between blood lymphocyte count and sITGb2 integrin subunit levels (R = −0.49 p = 0.01). (4) Conclusions: Elevated concentrations of sITGaM and sITGb2 were associated with long-term pulmonary complications in post-COVID-19 patients. Both sITGaM and sITGb2 may be promising biomarkers for predicting pulmonary complications and could be a potential target for therapeutic intervention in post-COVID-19 patients.

At the end of the last century, genetic studies reported that genetic information is not transmitted solely by DNA, but is also transmitted by other mechanisms, named as epigenetics. The well-described epigenetic mechanisms include DNA methylation, biochemical modifications of histones, and microRNAs. The role of altered epigenetics in the biology of various fibrotic diseases is well-established, and recent advances demonstrate its importance in the pathogenesis of pulmonary fibrosis-predominantly referring to idiopathic pulmonary fibrosis, the most lethal of the interstitial lung diseases. The deficiency in effective medications suggests an urgent need to better understand the underlying pathobiology. This review summarizes the current knowledge concerning epigenetic changes in pulmonary fibrosis and associations of these changes with several cellular pathways of known significance in its pathogenesis. It also designates the most promising substances for further research that may bring us closer to new therapeutic options.