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dc.contributorDepartment of Biomedical Engineeringen_US
dc.contributor.advisorWen, Chunyi (BME)en_US
dc.creatorNi, Junguo-
dc.identifier.urihttps://theses.lib.polyu.edu.hk/handle/200/13153-
dc.languageEnglishen_US
dc.publisherHong Kong Polytechnic Universityen_US
dc.rightsAll rights reserveden_US
dc.titleElucidating endothelin signalling in post-COVID skeletal sequelaeen_US
dcterms.abstractThe COVID-19 pandemic has posed a significant global challenge, with skeletal disorders emerging as common post-acute sequelae. Symptoms such as persistent joint aches and bone loss have been reported months after SARS-CoV-2 infection, but the exact pathomechanism remains unclear, and no effective cure has been found.en_US
dcterms.abstractEndothelial dysfunction and activation of endothelin signalling have been linked to the high prevalence of post-COVID-19 symptoms in patients. Notably, SARS-CoV-2 spike antigen has been observed in individuals with long COVID and detected in bronchial cartilage. However, the impact of endothelins and the spike protein on joint cartilage is still uncertain. This study hypothesizes that the synergistic effect of ET-1 and viral spike protein leakage from injured vessels could damage articular cartilage and growth plate in the sub-acute phase of SARS-CoV-2 infection. This research aimed to elucidate the role of endothelins in bone and joint after SARS-CoV-2 infection and explore the feasibility of using endothelin receptor blockers to treat post-COVID skeletal sequelae.en_US
dcterms.abstractWe demonstrated vascular damage with upregulation of serum ET-1 after SARS-CoVĀ­-2 infection in individuals and identified pathological damage in the vascular architecture of various organs with activation of endothelin signalling in the sub-acute phase of viral infection in hamsters.en_US
dcterms.abstractAdditionally, we investigated bone and joint injuries over time in a hamster model after SARS-CoV-2 infection. In the joint, we observed cyst formation at the osteochondral junction and chondrocyte dropout with systemic activation of endothelin signalling as early as 4 days post-infection (dpi), persisting for at least 30 days. In the bone, we observed growth plate disturbance and cyst formation after viral infection, with viral spike persistence in the bone at 30 dpi, causing chondrocyte death and growth plate thinning with upregulation of ET-1 and its receptors. We also demonstrated that bone turnover was inhibited after SARS-CoV-2 infection, reducing the new bone formation.en_US
dcterms.abstractMoreover, our study deciphered that endothelin signalling increased with endothelial dysfunction, leading to the leakage of spike protein into the bone marrow cavity, resulting in osteoblast precursor and chondrocyte loss. Using a 3D micromass model, we identified that the combination of SARS-CoV-2 anti-spike protein S1, viral spike protein, and ET-1 contributed to caspase-driven chondrocyte death. We also demonstrated that viral spike RBD-induced deterioration of joint structure, chondrocyte and osteoblast precursor loss with upregulated ET-1 in a mouse model. Inhibition of endothelin signalling could mitigate these effects in vitro and in vivo.en_US
dcterms.abstractFurthermore, our data showed that in the acute phase of viral infection, inhibiting endothelin receptors using the FDA-approved medicine Macitentan ameliorated cystic lesions, mitigated growth plate disorganization, preserved chondrocyte numbers, and activated osteoblast precursors. Even delayed Macitentan treatment during the sub-acute infection phase, it still suppressed caspase-driven chondrocyte death, rescued the growth plate disturbance, and activated bone remodelling.en_US
dcterms.abstractCollectively, our findings provided a unique insight into understanding joint cartilage and growth plate defects under the synergistic interaction of viral spike and endothelinĀ­-1 in the sub-acute phase of viral infection. Macitentan emerges as a repurposable medication candidate for treating bone and joint damage in post-acute COVID-19.en_US
dcterms.extentxxiii, 193 pages : color illustrationsen_US
dcterms.isPartOfPolyU Electronic Thesesen_US
dcterms.issued2024en_US
dcterms.educationalLevelPh.D.en_US
dcterms.educationalLevelAll Doctorateen_US
dcterms.LCSHPost COVID-19 condition (Disease) -- Treatmenten_US
dcterms.LCSHEndotheliumen_US
dcterms.LCSHBones -- Diseasesen_US
dcterms.LCSHJoints -- Diseasesen_US
dcterms.LCSHHong Kong Polytechnic University -- Dissertationsen_US
dcterms.accessRightsopen accessen_US

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