Glycocalyx and Oxidative Stress in Endothelial Function (Part 1) (GlikoOxEND)

The Role of Glycocalyx and Oxidative Stress in Endothelial Function (Part 1)

The primary research objective of the project is to determine the role of eGC in microvascular reactivity in CKD (cross-sectional study 1).

The main objective of the project is to increase the excellence and interdisciplinarity of scientific work at MEFOS by connecting researchers from different scientific fields, improving conditions and resources for scientific work, and increasing international cooperation, in line with strategic objective 1: raising scientific excellence. The results of the project could provide pathophysiological insight into the development and maintenance of endothelial dysfunction in CKD, as well as identify new biomarkers for CKD.

Study Overview

• Status: Recruiting
• Conditions: Chronic Kidney Disease Patients

Detailed Description

The primary objective of this project is to determine the role of endothelial glycocalyx (eGC) in impaired microvascular endothelium-dependent reactivity in patients with chronic kidney disease compared to healthy and hypertensive patients without complications (cross-sectional study 1).

Specific objective 1.1: Measure the reactivity of the peripheral microcirculation (using a laser Doppler blood flow meter) and the thickness of eGC (using Glycocheck) in the specified groups.

Specific objective 1.2: Quantify soluble markers of eGC, oxidative stress, and inflammation from serum samples and peripheral blood mononuclear cells (PBMC), as well as antioxidant capacity in the specified groups.

Specific objective 1.3: Determine the relationship between the results of functional tests, eGC, and markers from specific objective 1.2.

• Study Type: Observational
• Enrollment (Estimated): 105

Contacts and Locations

• Study Contact: Name: Ines Drenjančević, MD, PhD; Phone Number: +385912241406; Email: ines.drenjancevic@mefos.hr

Study Locations

• Croatia
  • Osijek, Croatia, 31000
    • Recruiting
    • Osijek University Hospital

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: Yes

• Sampling Method: Probability Sample

Study Population

Patients with CKD of hypertensive etiology, patients with hypertension and healthy volunteer subjects as controls.

Description

Inclusion Criteria:

• patients with CKD of hypertensive etiology (grades 1-2 and 3-5; eGFR CKD-EPI GFR ≥ 90 ml/min/1.73 m², i.e. < 60 mL/min/1.73 m2), non-diabetics, non-smokers
• patients with hypertension (according to ESH2023 Guidelines) without kidney damage (eGFR CKD-EPI >90 mL/min/1.73 m2) non-diabetics, non-smokers
• healthy volunteer subjects as controls

Exclusion Criteria:

• kidney disease of any other etiology except hypertension
• endocrine, autoimmune or inflammatory diseases that could affect kidney function.
• smoking
• diabetes

Study Plan

How is the study designed?

Number of groups / cohorts

3

Cohorts and Interventions

Group / Cohort
Chronic Kidney Disease (CKD) group; Patients with CKD of hypertensive etiology, stages 1-2 and 3-5 (eGFR CKD-EPI GFR ≥ 90 ml/min/1.73 m², i.e. < 60 mL/min/1.73 m2), non-diabetics, non-smokers
Hypertension (HT) group; Patients who have hypertension (according to ESH2023 Guidelines doi: 10.1097/HJH.0000000000003480) without kidney damage (eGFR CKD-EPI >90 mL/min/1.73 m2) non-diabetics, non-smokers
Normotensive (NT) group; Healthy volunteer subjects as controls

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Microvascular reactivity	Skin microvascular reactivity in patients with chronic kidney disease compared to hypertensive patients and healthy subjects - assessed by Laser Doppler flowmetry (post-occlusive reactive hyperemia, acetylcholine and sodium nitroprusside)	Baseline, at one time point (first visit to the laboratory)
Endothelial glycocalyx	Measurement of the thickness of eGC in the specified groups - measured by Glycocheck	Baseline, at one time point (first visit to the laboratory)

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Endothelial glycocalyx soluble markers	Quantification of soluble markers of eGC from serum or plasma samples in the specified groups - measured by ELISA assays (syndecan-1, syndecan-4, glypican-1, MMP-9)	Baseline, at one time point (first visit to the laboratory)
Concentration of MPO, 8-iso prostaglandin F2a, OxLDL, AOPP and intracellular oxidative stress production	Quantification of oxidative stress biomarkers from serum samples and peripheral blood mononuclear cells (PBMC) in the specified groups - measured by ELISA assays (MPO, 8-iso prostaglandin F2a, OxLDL, AOPP) and flow cytometry (intracellulare oxidative stress production; DCF-DA and DHE)	Baseline, at one time point (first visit to the laboratory)
Macrophage frequency	Quantification of inflammation from peripheral blood mononuclear cells (PBMC) in the specified groups - flow cytometry (macrophage frequency)	Baseline, at one time point (first visit to the laboratory)
Antioxidant enzyme (SOD, CAT, GPx) concentration and activity	Quantification of antioxidative enzyme concentration and activation from serum samples in the specified groups - measured by ELISA assays and UV-Vis spectrophotometry (SOD, GPx, CAT)	Baseline, at one time point (first visit to the laboratory)

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Blood pressure	Automatic oscillometric measurement of systolic and diastolic blood measurement (mmHg)	Baseline, at one time point (first visit to the laboratory)
Heart rate	Automatic oscillometric measurement of heart rate (bpm)	Baseline, at one time point (first visit to the laboratory)
Body composition	Body composition and body fluid status measurement by a four-terminal portable impedance analyzer. Based on the value of skin resistance (Ohm) empirically derived formulas (the original manufacturer's software) will be used to calculate the estimated Fat Free Mass (FFM kg) and Fat (Fat Mass kg).	Baseline, at one time point (first visit to the laboratory)
Body Mass Index	Weight and height will be combined to report BMI (kg/m2)	Baseline, at one time point (first visit to the laboratory)
Body fluid status: Estimation of Total Body Water (TBW L), Extracellular Water (ECW L), Intracellular Water (ICW L), Plasma Fluid (PF L) and Interstitial Fluid (IF L)	Body fluid status measurement by four-terminal portable impedance analyzer. A single impedance measurement is used to derive Total Body Water (TBW), Extracellular Water (ECW), Intracellular Water (ICW), Plasma Fluid (PF), and Interstitial Fluid (IF) using the manufacturer's software.	Baseline, at one time point (first visit to the laboratory)

Collaborators and Investigators

• Sponsor: Josip Juraj Strossmayer University of Osijek
• Investigators: Study Chair: Ines Drenjančević, MD, PhD, Faculty of Medicine Josip Juraj Strossmayer University of Osijek

Study record dates

Study Major Dates

• Study Start (Actual): October 1, 2025
• Primary Completion (Estimated): September 30, 2029
• Study Completion (Estimated): September 30, 2029

Study Registration Dates

• First Submitted: February 16, 2026
• First Submitted That Met QC Criteria: February 24, 2026
• First Posted (Actual): February 27, 2026

Study Record Updates

• Last Update Posted (Actual): March 2, 2026
• Last Update Submitted That Met QC Criteria: February 26, 2026
• Last Verified: October 1, 2025

More Information

Terms related to this study

• Keywords: Inflammation; Oxidative Stress; Renal Insufficiency, Chronic; Microcirculation; Endothelium; Glycocalyx
• Additional Relevant MeSH Terms: Urogenital Diseases; Pathologic Processes; Male Urogenital Diseases; Kidney Diseases; Urologic Diseases; Female Urogenital Diseases; Female Urogenital Diseases and Pregnancy Complications; Chronic Disease; Disease Attributes; Renal Insufficiency; Pathological Conditions, Signs and Symptoms; Inflammation; Renal Insufficiency, Chronic
• Other Study ID Numbers: 602-04/25-08/07

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No