Glycocalyx & vascular Research

Abstract

Advanced age is accompanied by arterial dysfunction, as well as a diminished glycocalyx, which may be linked to reduced high molecular weight–hyaluronan (HMW-HA) synthesis. However, the impact of glycocalyx deterioration in age-related arterial dysfunction is unknown. We sought to determine if manipulations in glycocalyx properties would alter arterial function. Tamoxifen-induced hyaluronan synthase 2 (Has2) reduction was used to decrease glycocalyx properties. Three weeks post-tamoxifen treatment, glycocalyx thickness was lower in Has2 knockout compared to wild-type mice (P<0.05). Has2 reduction induced arterial dysfunction, demonstrated by impaired endothelium-dependent dilation (EDD) and elevated aortic stiffness (P<0.05). To augment glycocalyx properties, old mice received 10 weeks of a glycocalyx-targeted therapy via Endocalyx™ (old+ECX), which contains HMW-HA and other glycocalyx components. Compared to old control mice, glycocalyx properties and EDD were augmented, and aortic stiffness decreased in old+ECX mice (P<0.05). Old+ECX mice had a more youthful aortic phenotype, demonstrated by lower collagen content and higher elastin content than old control mice (P<0.05). Functional outcomes were repeated in old mice that underwent a diet supplemented solely with HMW-HA (old+HA). Compared to old controls, glycocalyx properties and EDD were augmented, and aortic stiffness was lower in old+HA mice (P<0.05). We did not observe any differences between old+HA and old+ECX mice (P>0.05). Has2 reduction phenocopies age-related arterial dysfunction, while 10 weeks of glycocalyx-targeted therapy that restores the glycocalyx also ameliorates age-related arterial dysfunction. These findings suggest that the glycocalyx may be a viable therapeutic target to ameliorate age-related arterial dysfunction.

Abstract

Background: Mitochondrial, lysosomal, and peroxisomal dysfunction; defective autophagy; mitophagy; and pexophagy, as well as the loss of glycocalyx integrity are known contributors to initiation and progression of diverse kidney diseases. Those cellular organelles are tightly interactive in health, and during development of a disease, damage in one may propagate to others. By extension, it follows that restoring an individual defect may culminate in a broader restorative spectrum and improvement of cell and organ functions.

Summary: A novel strategy of reconditioning cellular organellar dysfunction, which we define as refurbishment of pathogenically pivotal intra- or extracellular elements, damaged in the course of disease and impeding restoration, is briefly outlined in this overview. Individual therapeutic reconditioning approaches targeting selected organelles are cataloged. We anticipate that the proposed reconditioning strategy in the future may enrich the arsenal of regenerative medicine and nephrology.

Key Message: The arsenal of regenerative medicine and nephrology consisting of organ transplantation, use of stem cells, cell-free approaches, cell reprogramming strategies, and organ engineering has been enriched by the reconditioning strategy. The latter is based on the recognition of two facts that (a) impairment of diverse cellular organelles contributes to pathogenesis of kidney disease and (b) individual organelles are functionally interactively coupled, which explains the “domino effect” leading to their dysfunction. Reconditioning takes advantage of these facts and, while initially directed to restore the function of individual cellular organelles, culminates in the propagation of a therapeutic intervention to account for improved cell and organ function. Examples of such interventions are briefly summarized along the presentation of defective cellular organelles contributing to pathogenesis of kidney disease.

Excerpt from section Therapeutic Interventions to Preserve and Repair Glycocalyx

Another potentially promising therapeutic approach is represented by Endocalyx ProTM (Microvascular Health Solutions, Salt Lake City, [UT], USA), a combination of natural products each endowed with individual properties to accelerate restoration and prevent excessive degradation of glycocalyx. It contains brown seaweed extract called Laminaria japonica, rich in fucoidan sulfate – a hybrid of HS and CS. The fucoidan repairs the glycocalyx and prevents its breakdown by inhibiting heparanase activity. Another component is a high molecular weight hyaluronan. It is supplemented with glucosamine sulfate, providing the building blocks for glycocalyx synthesis. Further components include a proprietary blend of polyphenol and flavonoids with added superoxide dismutase and catalase (both from bitter melon concentrate).

A new study using GlycoCheck, and co-authored by GlycoCheck Chief Science Officer, Dr. Hans Vink, reports new findings of research on patients with sepsis. The study, titled “Identification of novel sublingual parameters to analyze and diagnose microvascular dysfunction in sepsis: the NOSTRADAMUS study” was published in Critical Care. Critical Care is a high-quality, peer-reviewed, international clinical medical journal that provides a comprehensive overview of the intensive care field.

“For the first time, we can now determine quantitative microvascular scores that correlate very well with accepted clinical parameters in individual sepsis patients for a wide range of clinical severities,” said Dr. Vink, Co-Founder of GlycoCheck.

“The new GlycoCheck software system represents a significant upgrade for researchers and healthcare practitioners,” said Robert Long, CEO and Co-Founder of GlycoCheck and Microvascular Health Solutions. “For several years, GlycoCheck has been used globally in groundbreaking research to understand the complex nature of the endothelial glycocalyx.”

The study concludes that new important diameter-specific quantification and differentiated analysis of RBC kinetics is a key to understand microvascular dysfunction in sepsis. MVHSdynamic, which has a broad bandwidth to detect micro-vascular (dys-) function, might serve as a valuable tool to detect microvascular impairment in critically ill patients.

Abstract

Large elastic artery stiffening and endothelial dysfunction, and associated reductions in nitric oxide (NO) bioavailability, are central features of vascular aging. We have recently demonstrated that the glycocalyx, a gel-like structure that is bound to the luminal surface of the vascular endothelium, is dysfunctional in the aged vasculature. The glycocalyx has several functions that are critical for the maintenance of a healthy vasculature. We sought to determine if chronic dietary supplementation of glycocalyx precursors (glucosamine sulfate, fucoidan, superoxide dismutase, and high molecular weight hyaluronan) could restore glycocalyx function, while concomitantly ameliorating age-related vascular dysfunction. Young (Y: 7 mo) and old (O: 30 mo) male B6D2F1 mice consumed a control (C) or glycocalyx precursor (GP: 37 mg/kg encapsulated chow provided courtesy of MicroVascular Health Solutions, Inc. [U.S. Patent Serial No. 9,943,572]) diet ad libitum for 10 weeks. Glycocalyx barrier function (perfused boundary region [PBR]) was evaluated in the mesenteric microcirculation using an intravital microscope equipped with an automated capture and analysis system. PBR was ~13% higher in OC compared to YC, suggestive of an age-related impairment in glycocalyx barrier function, and this was normalized in OGP mice (Both P<0.05; Figure 1). At baseline, aortic pulse wave velocity (PWV), a measure of large artery stiffness, was higher in OC and OGP compared with YC mice (Both P<0.05; Figure 2). However, after the dietary intervention, PWV decreased by ~13% in OGP (P<0.05), whereas, PWV was unchanged in OC and YC mice after the 10 week period (P>0.05). We assessed endothelial function by endothelium-dependent dilation (EDD, maximal response to acetylcholine [ACh]) in the carotid artery. Carotid artery EDD was higher in YC and OGP compared to OC mice (92.5±2.4 and 90.7±2.3 vs. 69.0±4.9%, respectively, P<0.05). EDD of OGP was similar to YC mice (P>0.05). After incubation with the nitric oxide (NO) synthase inhibitor, L-NAME, the dilatory response did not differ between groups (P>0.05). NO bioavailability (max ACh dilation – max ACh+L-NAME dilation) was ~10–14 fold higher in YC and OGP compared to OC mice (Both P<0.05; Figure 3). Endothelium-independent dilation (vasodilation to sodium nitroprusside) was not different between groups (P>0.05). In young mice, GP diet did not affect any of the aforementioned measurements (P>0.05). In conclusion, 10 weeks of dietary GP supplementation in old mice restores glycocalyx barrier function that is accompanied by reduced aortic stiffness and augmented EDD and NO bioavailability, suggesting that the glycocalyx may be an effective therapeutic target for vascular dysfunction in older adults.

Summary of Findings from Clinical Studies

6.3.2 Food supplement
A pilot study was conducted among 13 healthy volunteers receiving the Endocalyx food supplement. After 3 months, the Microvascular Health Index measured by SDF imaging improved by 31%. After 4 months, the Microvascular Health Index in the volunteers improved by 50%. This showed the beneficial effects of the food supplement on the microvasculature as it significantly increased capillary density and red blood cell filling percentage, and reduced the perfused boundary region (unpublished data, H. Vink).

Summary of Known and Potential Risks and Benefits

6.4.2 Food supplement
In the pilot study with Endocalyx, no serious adverse effects were reported. One side effect that was reported was dizziness, as the Endocalyx supplement lowered the systolic blood pressure. The supplement is already used in general practitioners’ offices in the United States and to date; no one reported any major side effects. Studies conducted with the individual ingredients also did not report any serious adverse effects. A possible side effect may be an unknown allergic reaction to one of the ingredients of the supplement. Benefits of the Endocalyx food supplement in diabetic patients remain to be established but are mainly improving microvascular health by supporting endothelial glycocalyx function.

Clinical Trial Study

Sponsor:
Leiden University Medical Center

Collaborators:
Dutch Kidney Foundation
Health Holland
Radboud University

Subsidizing Party:
Health Holland (Dutch Top Sector Life Sciences & Health)
Laan van Nieuw Oost-Indië 334,
2593 CE Den Haag
The Netherlands

Dutch Kidney Foundation
Groot Hertoginnelaan 34
1405 EE, Bussum
The Netherlands

Laboratory Sites:
Leiden University Medical Center, The Netherlands
Radboud University Medical Center, The Netherlands

Objective:
To investigate whether intervention with the dietary supplement Endocalyx™ improves the
Microvascular Health Index between baseline and 3 months in type 2 diabetic South Asian patients with
microalbuminuria in comparison to the placebo group.