In our recent review on #LongCovid/PASC we bring up the possibility that dysbiosis or imbalance of host #microbiome communities (in ecosytems such as the gut, lungs, or oral cavity) might contribute to at least some LongCovid symptoms: frontiersin.org/articles/10.33… 
2/ More specifically immune dysregulation driven by #SARS-CoV-2 might allow pathobionts (bacteria capable of both commensal + virulent acitivty) in the gut, mouth, or other body sites to collectively shift towards a state of imbalance + pro-inflammatory gene/metabolite expression
3/ Conversely, b/c composition + activity of the microbiome can influence host susceptibility and ongoing control of #viral pathogens, exisiting microbiome dysbiosis in a range of body sites may serve as a form of predisposition to LongCovid
4/ Now, a team had performed a study of #oral microbiome dysbiosis in LongCovid that indeed suggests these trends deserve further study: df6sxcketz7bb.cloudfront.net/manuscripts/15…
5/ The team found that patients w/ chronic symptoms ~10 weeks after acute #COVID-19 (LongCovid) had significantly higher abundance of microbiome species that induce inflammation, such as members of the genera Prevotella and Veillonella
6/ Indeed, among several trends in the LongCovid subjects, modeling identified 1) microbial associations known to produce #inflammation via LPS production 2) reduction of anti-inflammatory #metabolic pathways
7/ One of the reasons this shift towards a pro-inflammatory LongCovid oral microbiome matters, is that it can lead to dysfunction of #oral barriers such as the gingiva, allowing organisms + their LPS/metabolites to “leak” into the #blood
8/ Once in the blood, the bacteria/LPS/metabolites may spark #immune activation, such as cytokine production, or drive other problems, such as formation of fibrinogen/coagulation. Some of the #bacteria may also be able to infect tissue or the vasculature
9/ This could lead to chronic symptoms on its own, or augment related SARS-CoV-2 inflammatory/coagulation-associated sequelae (eg: persistence of SARS-CoV-2 itself and/or its spike protein can also drive inflammation/clotting issues): cardiab.biomedcentral.com/articles/10.11…
10/ Going back to the initial study, the team also found that many of the bacterial genera increased in abundance in the oral #microbiome of their LongCovid subjects overlapped w/ those identified in this #ME/CFS oral microbiome study: pubmed.ncbi.nlm.nih.gov/30204780/
11/ That is not surprising, since many patients with #LongCovid meet the diagnostic criteria for ME/CFS. Overall it suggests there is value is studying patients with both diagnoses concurrently
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