ABSTRACT
Objective:To investigate the expression of coronavirus disease 2019 (COVID-19) transmission-related receptors angiotensin-converting enzyme 2 (ACE2) and transmembrane serine protease 2 (TMPRSS2) in human conjunctival tissue and its clinical significance.Methods:Fifty human conjunctival tissue specimens from 50 patients including 10 normal conjunctival tissues, 15 conjunctival papilloma tissues, 15 conjunctival nevus tissues and 10 conjunctival cyst tissues were collected from June 2019 to June 2020 at Xi'an People's Hospital.Ten corneal tissue samples from 10 patients with eyes removed due to trauma were collected as control.The distribution of ACE2 and TMPRSS2 in different corneal tissues was detected by the immunohistochemistry.The expression of ACE2 and TMPRSS2 was scored and compared.Reuse of the human samples and the research protocol was approved by an Ethics Committee of Xi'an People's Hospital (No.20190022). Written informed consent was obtained from each patient.Results:ACE2 and TMPRSS2 were both expressed in normal conjunctival epithelium, epithelial cells in conjunctiva papilloma and conjunctival nevus, and cells in conjunctiva cyst wall.ACE2 was mainly distributed in the superficial and intermediate cells of conjunctival epithelium, but not in the basal cells and goblet cells.TMPRSS2 was found in different layers of cells.The positive expression rates of ACE2 and TMPRSS2 in conjunctiva were both 100%.There was no significant difference in the expression intensity of ACE2 and TMPRSS2 among normal conjunctival tissue, conjunctival papilloma, conjunctival nevus and conjunctival cyst (all at P>0.05). Weakly expressed in corneal tissues, ACE2 and TMPRSS2 were more moderately and strongly expressed in conjunctival tissues.There were significant differences in the number of differently graded ACE2 and TMPRSS2 expression between normal conjunctival tissues, conjunctival papilloma, conjunctival nevus, conjunctival cyst and corneal tissues (ACE2: Z=-3.473, -4.183, -3.970, -3.873, all at P<0.01; TMPRSS2: Z=-4.119, -4.472, -4.443, -4.147, all at P<0.001). Conclusions:COVID-19 transmission-related receptors ACE2 and TMPRSS2 are expressed in human conjunctival tissue, which provides organological evidence for ocular surface transmission of COVID-19.
ABSTRACT
Although children usually develop less severe disease responding to COVID-19 than adults, little is known about the pathogenesis of COVID-19 in children. Herein, we conducted the plasma proteomic and metabolomic profiling of a cohort of COVID-19 pediatric patients with mild symptoms. Our data show that numerous proteins and metabolites involved in immune as well as anti-inflammatory processes were up-regulated on a larger scale in children than in adults. By developing a machine learning-based pipeline, we prioritized two sets of biomarker combinations, and identified 5 proteins and 5 metabolites as potential children-specific COVID-19 biomarkers. Further study showed that these identified metabolites not only inhibited the expression of pro-inflammatory factors, but also suppressed coronaviral replication, implying that these factors played key roles in protecting pediatric patients from both viral infection and infection-induced inflammation. Together, our study uncovered a protective mechanism responding to COVID-19 in children, and sheds light on potential therapies. TeaserAnti-inflammatory metabolites were highly elevated in the plasma of COVID-19 pediatric patients with mild symptoms.
ABSTRACT
The pandemic of the coronavirus disease 2019 (COVID-19) has become a global public health crisis. The symptoms of COVID-19 range from mild to severe conditions. However, the physiological changes associated with COVID-19 are barely understood. In this study, we performed targeted metabolomic and lipidomic analyses of plasma from a cohort of COVID-19 patients who had experienced different symptoms. We found the metabolite and lipid alterations exhibit apparent correlation with the course of disease in these COVID-19 patients, indicating that the development of COVID-19 affected whole-body metabolism of the patients. In particular, malic acid of the TCA cycle and carbamoyl phosphate of urea cycle reveal the altered energy metabolism and hepatic dysfunction, respectively. It should be noted that carbamoyl phosphate is profoundly down-regulated in fatal patients compared with mild patients. And more importantly, guanosine monophosphate (GMP), which is mediated by not only GMP synthase but also CD39 and CD73, is significant changed between healthy subjects and COVID-19 patients, as well as between the mild and fatal groups. In addition, the dyslipidaemia was observed in COVID-19 patients. Overall, the disturbed metabolic patterns have been found to align with the progress and severity of COVID-19. This work provides valuable knowledge about plasma biomarkers associated with COVID- 19 and potential therapeutic targets, as well as important resource for further studies of COVID-19 pathogenesis.
