# Effects of 4‐month treatment with glycocalyx dietary supplement on endothelial glycocalyx and vascular function after COVID‐19 infection

## TL;DR

A 4-month glycocalyx supplement improved vascular health and reduced oxidative stress in post-COVID-19 patients.

## Contribution

Shows that a dietary supplement can improve endothelial function and reduce post-COVID symptoms.

## Key findings

- GDS reduced oxidative stress markers and improved coronary flow reserve compared to placebo.
- Patients on GDS had fewer post-COVID symptoms after treatment.
- Improvements in vascular function correlated with reduced oxidative stress.

## Abstract

Coronavirus disease 2019 (COVID‐19) has been associated with impaired endothelial and vascular function. We investigated whether intervention with glycocalyx dietary supplement (GDS), containing glucosamine sulfate and fucoidan, improves endothelial glycocalyx and vascular function after COVID‐19 infection.

Fifty‐seven convalescent patients 14 days after mild‐to‐moderate COVID‐19 infection managed in an outpatient setting were randomized to receive GDS (n = 29) or placebo (n = 28) for 4 consecutive months. We measured at baseline and at 4 months: (a) perfused boundary region (PBR) of the sublingual microvessels with a diameter range of 4–25 μm, as a marker of endothelial glycocalyx integrity, (b) pulse wave velocity and augmentation index, (c) coronary flow reserve using Doppler echocardiography, and (d) malondialdehyde and protein carbonyls as oxidative stress markers.

Four months after treatment, patients who received GDS showed a greater reduction in PBR 4–25 μm (−6.8% vs. −1.3%), pulse wave velocity (−13.2% vs. −3%), augmentation index (−28.5% vs. −2.5%), malondialdehyde (−26% vs. −2.9%), protein carbonyls (−31.3% vs. −1%) and a greater increase in coronary flow reserve (12.9% vs. 1.6%) compared to placebo (p < .05). In the GDS group, the reduction in PBR 4–25 μm was associated with the corresponding decrease in pulse wave velocity (r = .31, p = .047), malondialdehyde, and protein carbonyls, as well as with the increase in coronary flow reserve (r = −.59, p = .008) at follow‐up. Post‐treatment, none of the patients under GDS reported post‐COVID symptoms compared to 21.4% of the patients under placebo.

Four‐month treatment with GDS may improve endothelial glycocalyx and vascular function after COVID‐19 infection.

URL: https://www.clinicaltrials.gov. Unique identifier: NCT05185934.

The present study aimed to investigate the effect of glycocalyx dietary supplement (GDS), containing glucosamine sulfate and fucoidan, on endothelial glycocalyx integrity and vascular function in subjects after mild‐to‐moderate COVID‐19 infection managed in an outpatient setting. Four‐month administration of GDS resulted in significant improvement in endothelial glycocalyx integrity, vascular function, and coronary microcirculation in conjunction with a substantial reduction in oxidative stress. These findings suggest that GDS administration for a short‐term period might mitigate or prevent potential subclinical COVID‐19‐related cardiovascular complications.