Effects of Arthrospira platensis biomass on risk factors associated with metabolic syndrome

Background: Arthrospira platensis is a source of macro and micronutrients, including proteins, γ-linolenic acid and bioactive pigments such as phycocyanin. Some clinical studies on obese and overweight people suggested that this microalga might help in controlling some aspects of metabolic disorders, primarily dyslipidemia. Experimental studies have also highlighted the ability of some peptides from A. platensis biomass or deriving from phycocyanin, to decrease blood pressure, in spontaneously hypertensive rats. Aim: The aim of our work was to analyse the effects of a diet enriched with 5% biomass of A. platensis F&M-C256 on vascular and metabolic alterations induced by a diet rich in fats. Methods: Male Sprague Dawley rats were fed for 12 weeks with: i) a standard AIN-76 diet (control; n = 8); ii) a diet rich in saturated fats (30% of lard, HFD; n = 8); iii) a HFD diet supplemented with 5% (w/w) A. platensis F&M-C256 (AHFD; n = 8). Results: At the end of the experiment, AHFD fed rats had no significant changes in body weight and on visceral, renal and epididymal fat deposits compared to the HFD group, however they showed significantly lower serum concentrations of triglycerides and total cholesterol, compared to HFD fed animals. These effects were associated to an increased faecal lipid excretion and to a significantly reduction of 3-hydroxy-3-methyl-glutaryl-coenzyme A reductase (HMGCR) hepatic gene expression. Moreover, A. platensis F&M-C256 rich-diet significantly affected blood pressure values: systolic and diastolic blood pressure were in fact, both significantly lower in rat fed AHFD compared to rats fed with the HFD diet (-15 and -35%, respectively). We found also a significant reduction of angiotensin receptor (AT1) expression and an increased level of endothelial NO synthase (eNOS) in the aortic arch of rats fed the A. platensis F&M-C256-rich diet compared to HFD fed rats. Conclusions and discussion: Our data indicate that A. platensis F&M-C256 biomass contains compounds able to affect the renin angiotensin system and to regulate nitric oxide (NO) production and suggest that the consumption of foods enriched with A. platensis biomass could be explored as complementary strategy to conventional treatments for the control of hypertension.