Search

Background: The value of extracorporeal membrane oxygenation (ECMO) for patients suffering from novel coronavirus disease 2019 (COVID-19) as a rescue therapy for respiratory failure remains controversial and associated with high mortality rates of 50 to 82% in early reports from Wuhan, China. We hypothesized that patient outcomes would be improved at our tertiary cardiothoracic surgery referral center with a protocolized team-approach for ECMO treatment of patients with severe COVID-19 disease., Case Presentation: A 51-year-old healthy female developed severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) bilateral pneumonia while vacationing in Colorado with her family. She was transferred to our facility for a higher level of care. Her respiratory status continued to deteriorate despite maximized critical care, including prone positioning ventilation and nitric oxide inhalation therapy. Veno-venous ECMO was initiated on hospital day 7 in conjunction with a 10-day course of compassionate use antiviral treatment with remdesivir. The patient's condition improved significantly and she was decannulated from ECMO on hospital day 17 (ECMO day 11). She was successfully extubated and eventually discharged to rehabilitation on hospital day 28., Conclusion: This case report demonstrates a positive outcome in a young patient with COVID-19 treated by the judicious application of ECMO in conjunction with compassionate use antiviral treatment (remdesivir). Future prospective multi-center studies are needed to validate these findings in a larger cohort of patients., Competing Interests: Competing interestsMSF has served as scientific and educational consultant to Maquet Cardiovascular LLC, and as such has received funding for travel and financial support for educational activities related to ECMO technology. PFS is employed by HCA Healthcare in his role as the Chief Medical Officer at the Medical Center of Aurora. None of the other authors have relevant disclosures or conflicts of interest related to this manuscript. The CardioHelp™ extra-corporeal support system (Maquet Cardiovascular, Wayne, NJ) is not approved by the United States Food and Drug Administration for long-term use as described in this report., (© The Author(s) 2020.)

Pulmonary hypertension (PH) is characterized by sustained vasoconstriction, with subsequent extracellular matrix (ECM) production and smooth muscle cell (SMC) proliferation. Changes in the ECM can modulate vasoreactivity and SMC contraction. Galectin-1 (Gal-1) is a hypoxia-inducible beta-galactoside-binding lectin produced by vascular, interstitial, epithelial, and immune cells. Gal-1 regulates SMC differentiation, proliferation, and apoptosis via interactions with the ECM, as well as immune system function, and, therefore, likely plays a role in the pathogenesis of PH. We investigated the effects of Gal-1 during hypoxic PH by quantifying 1) Gal-1 expression in response to hypoxia in vitro and in vivo and 2) the effect of Gal-1 gene deletion on the magnitude of the PH response to chronic hypoxia in vivo. By constructing and screening a subtractive library, we found that acute hypoxia increases expression of Gal-1 mRNA in isolated pulmonary mesenchymal cells. In wild-type (WT) mice, Gal-1 immunoreactivity increased after 6 wk of hypoxia. Increased expression of Gal-1 protein was confirmed by quantitative Western analysis. Gal-1 knockout (Gal-1(-/-)) mice showed a decreased PH response, as measured by right ventricular pressure and the ratio of right ventricular to left ventricular + septum wet weight compared with their WT counterparts. However, the number and degree of muscularized vessels increased similarly in WT and Gal-1(-/-) mice. In response to chronic hypoxia, the decrease in factor 8-positive microvessel density was similar in both groups. Vasoreactivity of WT and Gal-1(-/-) mice was tested in vivo and with use of isolated perfused lungs exposed to acute hypoxia. Acute hypoxia caused a significant increase in RV pressure in wild-type and Gal-1(-/-) mice; however, the response of the Gal-1(-/-) mice was greater. These results suggest that Gal-1 influences the contractile response to hypoxia and subsequent remodeling during hypoxia-induced PH, which influences disease progression.

Tight regulation of VEGF-A production and signaling is important for the maintenance of lung development and homeostasis. VEGF null mice have provided little insight into the role of VEGF during the later stages of lung morphogenesis. Therefore, we examined the in vitro effects of autocrine and paracrine VEGF-A production and the inhibition of VEGF-A signaling on a Flk-1-negative subset of fetal pulmonary mesenchymal cells (pMC). We hypothesized that VEGF-A receptor signaling regulates turnover of fetal lung mesenchyme in a cell cycle-dependent manner. VEGF receptor blockade with SU-5416 caused cell spreading and decreased proliferation and bcl-2 localization. Nuclear expression of the cell cycle inhibitory protein, p21, was increased with SU-5416 treatment, and p27 was absent. Autocrine VEGF production by pMC resulted in proliferation and p21/p27-dependent contact inhibition. In contrast, exogenous VEGF-A increased cell progression through the cell cycle. Selective activation of Flt by placental growth factor demonstrated the importance of this receptor/kinase in the VEGF-A responsiveness of pMC. The expression and localization of the survival factor bcl-2 was dependent on VEGF. These results provide evidence that VEGF-A plays a critical role in the regulation of fetal pulmonary mesenchymal proliferation, survival, and the subsequent development of normal lung architecture through bcl-2 and p21/p27-dependent cell cycle control.