Interaction between bacteria and SARS-CoV-2
It is known from various studies and also from RIVM data that obesity, diabetes and cardiovascular diseases increase the risk of a serious course of Covid-19 (1,2). A few weeks ago, an intriguing review (3) appeared in which a synergistic effect is seen between the new coronavirus and lipopolysaccharide (LPS, an endotoxin of bacterial origin). Both decrease the expression of the ACE2 receptor in the lungs, thereby disrupting the angiotensin system. Research with a swine coronavirus has shown that the combination of that virus and LPS leads to severe acute respiratory syndrome (SARS) in pigs, while exposure to each alone produces much milder symptoms. Increased intestinal permeability is also seen in diabetes, among others (4), which leads to increased LPS in the circulation and associated insulin resistance (5). This review (3) is therefore a new indication that improving intestinal barrier function appears to be a useful therapeutic target to protect patients with cardiometabolic diseases.
Mycobiome in Alzheimer’s
Previous studies have already shown that there are differences in microbiome composition between Alzheimer’s patients and healthy individuals (6,7). These studies looked only at bacteria, but the human microbiome is also made up of many other types of microorganisms such as fungi, archea, protists, and viruses. A new publication concludes that there are also differences in the composition of fungi (the mycobiome) in people with mild cognitive decline (8). The researchers also compared the influence of two dietary patterns. Only a modified Mediterranean ketogenic diet appears to affect the mycobiome in patients with mild cognitive decline. This ties in with previous research in which this diet led to improvements in markers of Alzheimer’s disease. Another recent study using an animal model of Alzheimer’s convincingly demonstrates that fecal transplantation from healthy mice to diseased mice leads to reduced deposition of amyloid-β plaques, decreased inflammatory markers, and reduction of cognitive decline (9). These two studies expand the growing body of evidence that the disease process behind Alzheimer’s disease can be influenced via the gut.
References
- https://doi.org/10.1016/j.dsx.2020.04.044
- https://www.rivm.nl/documenten/wekelijkse-update-epidemiologische-situatie-covid-19-in-nederland
- https://doi.org/10.7554/eLife.61330
- https://doi.org/10.1186/1475-2891-13-60
- https://doi.org/10.2337/db06-1491
- https://doi.org/10.1038/s41598-017-13601-y
- https://doi.org/10.1038/s41598-018-38218-7
- https://doi.org/10.1016/j.ebiom.2020.102950
- https://doi.org/10.1136/gutjnl-2018-317431