Impact of inhibition of the renin-angiotensin system on early cardiac and renal abnormalities in Sprague Dawley rats fed short-term high fructose plus high salt diet.
Study Goal
The researchers aimed to determine whether chronic inhibition of the renin-angiotensin system (RAS) could restore blood pressure and improve cardiorenal function in rats fed a high fructose and high salt diet.
Results Summary
The study found that high fructose and high salt diets elevated blood pressure and caused cardiac and renal damage in rats, which was improved by RAS inhibitors (enalapril or losartan). Functional improvements in cardiorenal parameters were noted, though some effects were sex-specific.
Population
Male and female Sprague Dawley rats
Effective Dosage
Enalapril (4 mg/kg/d), losartan (8 mg/kg/d)
Duration
25-26 days
Interactions
None mentioned
| Intervention | Direction | Endpoint | Population | Dosage | Impact | Claim # |
|---|---|---|---|---|---|---|
high fructose and high salt diet | increase | high blood pressure | rodents | - | induces | #1 |
high fructose and high salt diet | increase | aortic stiffening | rodents | - | induces | #2 |
high fructose and high salt diet | increase | left ventricular (LV) diastolic dysfunction | rodents | - | induces | #3 |
high fructose and high salt diet | increase | impaired renal function | rodents | - | induces | #4 |
acute inhibition of the RAS pathway | no change | cardiac and vascular parameters | rats fed high fructose and high salt | - | does not improve | #5 |
chronic RAS inhibition | decrease | blood pressure (BP) | fructose+high salt-fed rats | to levels similar to glucose plus normal salt-fed controls | restore | #6 |
fructose+high salt diet | increase | BP | fructose+high salt groups of both sexes | - | elevated | #7 |
Enalapril (Enal, 4 mg/kg/d) | decrease | BP | fructose+high salt groups of both sexes | to control levels | restored | #8 |
Losartan (Los, 8 mg/kg/d) | decrease | BP | fructose+high salt groups of both sexes | to control levels | restored | #9 |
Losartan (Los, 8 mg/kg/d) | decrease | Pulse wave velocity (PWV) | female F+Los rats | - | was lower | #10 |
Enalapril (Enal, 4 mg/kg/d) | increase | cardiac output | female F+Enal rats | - | higher | #11 |
diet or treatment | no change | GFR | - | - | not changed | #12 |
fructose+high salt diet | increase | albuminuria | fructose+high salt groups of both sexes | - | displayed higher | #13 |
Enalapril (Enal, 4 mg/kg/d) | decrease | albuminuria | male rats | - | decreased | #14 |
fructose+high salt diet | increase | cardiac fibrosis | fructose+high salt-fed rats of both sexes | - | were greater | #15 |
fructose+high salt diet | increase | mesangial hypercellularity | fructose+high salt-fed rats of both sexes | - | were greater | #16 |
Losartan (Los, 8 mg/kg/d) | decrease | cardiac fibrosis and mesangial hypercellularity | fructose+high salt-fed rats of both sexes | - | improved | #17 |
Enalapril (Enal, 4 mg/kg/d) | decrease | cardiac fibrosis and mesangial hypercellularity | fructose+high salt-fed rats of both sexes | - | improved | #18 |
inhibition of the RAS | decrease | early changes in cardiac and renal histopathology | both sexes | - | improves | #19 |
inhibition of the RAS | decrease | albuminuria | male rats fed high fructose and high salt diet | - | improves | #20 |
INTRODUCTION: The combination of a high fructose and high salt diet typical of western diet induces high blood pressure, aortic stiffening, left ventricular (LV) diastolic dysfunction and impaired renal function in rodents. Despite an activated renin-angiotensin system (RAS) in rats fed high fructose and high salt, acute inhibition of the RAS pathway does not improve cardiac and vascular parameters. It may well be that longer term treatment is required to permit remodeling and improve cardiovascular function. Thus, we hypothesized that chronic RAS inhibition fructose+high salt-fed rats to restore blood pressure (BP) to levels similar to glucose plus normal salt-fed controls will improve cardiorenal function and histopathology. METHODS: Male and female Sprague Dawley rats monitored by hemodynamic telemetry were fed 0.4% NaCl chow during baseline, then changed to chow containing either 20% glucose+0.4% NaCl (G) or 20% fructose+4% NaCl (F) and treated with vehicle, enalapril (Enal, 4 mg/kg/d) or losartan (Los, 8 mg/kg/d) by osmotic minipump for 25-26 days. RESULTS: BP was elevated in the fructose+high salt groups of both sexes (P < 0.05) and restored to control levels by Enal or Los. Pulse wave velocity (PWV) was lower in female F+Los rats and cardiac output higher in female F+Enal rats. GFR was not changed by diet or treatment. Fructose+high salt groups of both sexes displayed higher albuminuria that was decreased by Enal in male rats. Cardiac fibrosis and mesangial hypercellularity were greater in fructose+high salt-fed rats of both sexes and improved with either Los or Enal. DISCUSSION: Thus, inhibition of the RAS improves early changes in cardiac and renal histopathology in both sexes and albuminuria in male rats fed high fructose and high salt diet. Functional improvements in cardiorenal parameters may require longer treatment.