The Effect of Sodium on Erythrocyte Salt Sensitivity, Syndecan-1 and Heparin Sulfate in Healthy Subjects.

The Effect of Sodium on Erythrocyte Salt Sensitivity, Syndecan-1 and Heparin Sulfate in Healthy Subjects: A Randomized, Double-Blinded, Placebo-Controlled, Cross-Over Study

The study was a double-blinded, randomized, placebo-controlled cross-over study. 27 healthy subjects received a four days standardized, sodium reduced diet (100 mmol sodium) and treatment with sodium chloride (200 mmol sodium) or placebo in a randomized order. After the treatment the subjects went to an examination day. With 1 L isotonic sodium chlorid intravenous in 25 minutes, the subjects were further sodium and volume loaded. Change in salt blood test (SaBT), syndecan-1(syn-1) and heparan sulfate (HS), brachial and central blood pressure (BP), pulse wave velocity (PWV) and augmentation index (AIx) were measured. Baseline blood samples were taken before the treatment periods

Background: The endothelium is lined with endothelial glycocalyx (EG). EG protects the endothelium and functions as a barrier between blood and endothelium. Due to negative charges EG has a strong ability to buffer sodium. In vitro studies indicate that sodium overload can damage the EG and reduce the sodium buffer capacity. This could cause endothelial dysfunction and might lead to cardiovascular disease. EG can be measured by the erythrocyte salt sensitivity (ESS) and shedding of glycocalyx.

Purpose: The investigators aimed to examine the effect of dietary sodium balance on EG in healthy subjects.

Methods: In a double blinded, randomized, placebo controlled cross over study, 27 healthy subjects received a four days sodium reduced diet and treatment with NaCl or placebo in randomized order. Afterwards the subjects were further sodium and volume loaded with 1 L isotonic NaCl intravenously. Changes in ESS and blood pressure were measured.

Inclusion Criteria:

• Both gender
• Age 18-50 years,
• BMI 18.5-30.0 kg/m2,
• Signed concent.
• Fertile women with safe contraception during the whole examination period.

Exclusion Criteria:

• Alcohol consumption > 7 drinks per week for women and, > 14 drinks per week for men.
• Smoking,
• Substance abuse
• Current use of medicine except contraception,
• Office BP > 140/90
• History or signs of clinically relevant kidney, heart, liver, lung, neurological, or endocrine diseases, neoplastic disorders,
• Pregnancy or lactation
• Blood donation within 1 month of the first investigation,
• Clinically relevant abnormal blood/urine sample or electrocardiography.

Withdrawal criteria:

• Development of exclusion criteria
• Suspicion of poor compliance to study medication
• Withdrawal of signed concent.