In persistent covid syndrome, the arterioles of the eye constrict and the venules react less intensely to light impulses, so a standardized eye exam could reveal in the future whether a person suffers from persistent covid syndrome, according to new research from the Technical University of Munich (TUM) in Germany that has shown a clear relationship between the disease and certain changes in the blood vessels of the eye.
Between 10% and 35% of those affected by this syndrome continue to experience symptoms such as breathing problems or fatigue long after contracting covid. Until now they are not known physical characteristics, or the so-called biomarkers, that can be used to reliably diagnose persistent covid.
One of the characteristics of covid-19 are changes in blood vessels. This affects the endothelium, specifically, the inner wall of the blood vessel. As a result of the changes, the body’s organs do not receive sufficient blood supply.
To date, the blood vessels studied were mainly large vessels. “However the 90% of the body’s endothelial cells are found in small and tiny glasses. It is barely known what happens to these blood vessels in persistent covid,” says the head doctor of the Department of Nephrology at the Klinikum rechts der Isar of the TUM university hospital and leader of the study, Christoph Schmaderer.
“The blood vessels of the eye could offer a clue about the state of small blood vessels throughout the body,” says Schmaderer. methods and tools necessary are well proven and do not require any intervention in the body.
In the findings, published in the ‘Angiogenesis’ magazine, two values showed a strong correlation with persistent covid. First of all, the arterioles, That is, the smaller arteries, were significantly narrowed compared to the healthy control group. Second, venules, but not arterioles, showed an altered response to light stimulation. Shining a flickering light into the eye causes the blood vessels to dilate. In the case of patients with persistent covid, this response was significantly reduced.
How many more inflammatory markers were measured in the participants’ blood, the more pronounced the changes. According to studies, it is suspected that persistent inflammatory responses They are another important factor in persistent covid.
However, since the study is comparatively small, with 41 sick participants, and it was only carried out in a single hospital, it cannot yet be deduced from the results no reliable test for long covid. In the opinion of the researchers, more studies are needed to verify the results.
“I am confident that from our results a diagnostic tool persistent covid,” says Christoph Schmaderer. “We also assume that the microcirculation is restricted, not only in the eye, but also in other parts of the body. “This could make the method especially suitable for evaluating the effectiveness of future therapies for persistent Covid,” he adds.
Source of data and images: elperiodico