Tissue Inhibitor of Matrix Metalloproteinases-1 (TIMP-1) and Pulmonary Involvement in COVID-19 Pneumonia

Abstract

Background: The aim of the study was to longitudinally evaluate the association between MMP-2, MMP-9, TIMP-1 and chest radiological findings in COVID-19 patients. Methods: COVID-19 patients were evaluated based on their hospital admission (baseline) and three months after hospital discharge (T post) and were stratified into ARDS and non-ARDS groups. As a control group, healthy donors (HD) were enrolled. Results: At the baseline, compared to HD (n = 53), COVID-19 patients (n = 129) showed higher plasma levels of MMP-9 (p < 0.0001) and TIMP-1 (p < 0.0001) and the higher plasma activity of MMP-2 (p < 0.0001) and MMP-9 (p < 0.0001). In the ARDS group, higher plasma levels of MMP-9 (p = 0.0339) and TIMP-1 (p = 0.0044) and the plasma activity of MMP-2 (p = 0.0258) and MMP-9 (p = 0.0021) compared to non-ARDS was observed. A positive correlation between the plasma levels of TIMP-1 and chest computed tomography (CT) score (ρ = 0.2302, p = 0.0160) was observed. At the T post, a reduction in plasma levels of TIMP-1 (p < 0.0001), whereas an increase in the plasma levels of MMP-9 was observed (p = 0.0088). Conclusions: The positive correlation between TIMP-1 with chest CT scores highlights its potential use as a marker of fibrotic burden. At T post, the increase in plasma levels of MMP-9 and the reduction in plasma levels of TIMP-1 suggested that inflammation and fibrosis resolution were still ongoing.

Keywords: ELISA; MMP-2; MMP-9; PASC; computed tomography; matrix metalloproteinases; post-acute sequelae of SARS-CoV-2 infection; pulmonary fibrosis; sCD14; sCD163; zymography.

Figure 1

Next-generation ELISA and gelatin zymography data at the baseline. Plasma levels of MMP-9 (A), TIMP-1 (B), MMP-9/TIMP-1 ratio (C), sCD163 (F) and sCD14 (G), as well as the plasma activity of MMP-2 (D), and MMP-9 (E) were evaluated in COVID-19 patients (dashed line box on the left) and HD (dashed line box on the right), was stratified according to ARDS development. The differences between the total population of COVID-19 patients, and HD were evaluated using the nonparametric Mann–Whitney test. The differences between ARDS, non-ARDS groups and HD were assessed using the nonparametric Kruskal–Wallis test with Dunn’s post-test. Horizontal lines represent medians. ARDS: acute respiratory distress syndrome; HD: healthy donors; MMP-9: matrix metalloproteinase-9; TIMP-1: tissue inhibitor of metalloproteinase-1; MMP-2: matrix metalloproteinase-2; OD: optical density; sCD163: soluble CD163; sCD14: soluble CD14. *: 0.05 < p < 0.01; **: 0.01 < p < 0.001; ***: 0.001 < p < 0.0001; ****: p > 0.0001.

Figure 2

Correlations between baseline plasma levels of MMP-9 and TIMP-1 with clinical data. The correlation between levels of MMP-9 and TIMP-1 with the clinical parameters was evaluated in plasma samples from COVID-19 patients collected at the time of hospital admission using the regression test. A positive correlation was detected between plasma levels of MMP-9 and WBC (R² = 0.2156, p < 0.0001) (A); neutrophil absolute count (R² = 0.2449, p < 0.0001) (B); NLR (R² = 0.4261, p < 0.0001) (C); and CRP (R² = 0.6960, p = 0.0049) (D). A negative correlation was detected between plasma levels of MMP-9 and the P/F ratio (R² = 0.06696, p = 0.0042) (E). A positive correlation was detected between plasma levels of TIMP-1 and WBC (R² = 0.07493, p = 0.0022) (F); neutrophil absolute count (R² = 0.08855, p = 0.0009) (G); NLR (R² = 0.3227, p = 0.0003) (H); CRP (R² = 0.2404, p = 0.0115) (I); D-dimer (R² = 0.3812, p < 0.0001) (J); ferritin (R² = 0.1833, p < 0.0001) (K); LDH (R² = 0.09266, p = 0.0008) (L); sCD163 (R² = 0.03857, p = 0.0257) (M); and chest CT score (R² = 0.0.07575, p = 0.0038) (O). A negative correlation was detected between plasma levels of TIMP-1 and the P/F ratio (R² = 0.05672, p = 0.0085) (N). All correlations were performed using the Spearman test. Spearman coefficient (ρ) and statistical significance (p) are reported in the graphics. MMP-9: matrix metalloproteinase-9; TIMP-1: tissue inhibitor of metalloproteinase-1; WBC: white blood cells; N: neutrophils; NLR: neutrophil/lymphocyte ratio; CRP: C-reactive protein; LDH: lactate dehydrogenase; sCD163: soluble CD163; P/F: arterial oxygen partial pressure/fraction of inspired oxygen; CT: computed tomography.

Figure 3

Longitudinal evaluation of clinical data. Longitudinal evaluation of WBC count (A), N absolute count (B), L absolute count (C), and NLR (D), as well as the plasmatic levels of CRP (E), D-dimer (F), ferritin (G), LDH (H) and the chest CT score (I), were performed using the Wilcoxon test. Baseline: on hospital admission; T post: three months from hospital discharge; WBC: white blood cells; N: neutrophils; L: lymphocytes; NLR: neutrophil/lymphocyte ratio; CRP: C-reactive protein; LDH: lactate dehydrogenase; CT: computed tomography. ***: 0.001 < p < 0.0001; ****: p > 0.0001.

Figure 4

Longitudinal evaluation of next-generation ELISA and gelatin zymography data. Plasma levels of MMP-9 (A), TIMP-1 (B), MMP-9/TIMP-1 ratio (C), sCD163 (F), and sCD14 (G), as well as the plasma activity of MMP-2 (D) and MMP-9 (E), were evaluated in COVID-19 patients at two time-points: on hospital admission (baseline) and three months from hospital discharge (T post). The differences were evaluated using the nonparametric Wilcoxon test. Moreover, the differences between both time points and HD were assessed using the nonparametric Kruskal–Wallis test with Dunn’s post-test. Horizontal lines represent medians. ARDS: acute respiratory distress syndrome; HD: healthy donors; MMP-2: matrix metalloproteinase-2; MMP-9: matrix metalloproteinase-9; TIMP-1: tissue inhibitor of metalloproteinase-1; OD: optical density; sCD163: soluble CD163; sCD14: soluble CD14. * 0.05 < p < 0.01; ** 0.01 < p < 0.001; *** 0.001 < p < 0.0001; **** p > 0.0001.