Urinary metabolomics, dietary salt intake and blood pressure: the African-PREDICT study.

In Black populations excessive salt intake may exacerbate the genetic predisposition to hypertension and promote the early onset of cardiovascular disease. Ethnic differences in the interaction between sodium intake and the metabolome may play a part in hypertension and cardiovascular disease development. We determined (1) urinary amino acid and acylcarnitine profiles of young Black and White adults according to low, moderate, and high dietary salt intake, and (2) investigated the triad of salt intake, systolic blood pressure (SBP), and the associated metabolomics profile. This study included 447 White and 380 Black adults aged 20-30 years from the African-PREDICT study. Estimated salt intake was determined from 24-hour urinary sodium levels. Urinary amino acids and acylcarnitines were measured using liquid chromatography-tandem mass spectrometry. Black adults exhibited no significant differences in SBP, amino acids, or acylcarnitines across low (<5g/day), moderate (5-10g/day), and high (>10g/day) salt intake. White adults with a high salt intake had elevated SBP compared to those with low or moderate intakes (p < 0.001). Furthermore, gamma-aminobutyric acid (GABA) (q = 0.020), citrulline (q = 0.020), glutamic acid (q = 0.046), serine (q = 0.054) and proline (q = 0.054) were lowest in those with higher salt intake. Only in White and not Black adults did we observe inverse associations of clinic SBP with GABA (Adj. R2 = 0.34; Std. ß = -0.133; p = 0.003), serine (Adj. R2 = 0.33; Std. ß = -0.109; p = 0.014) and proline (Adj. R2 = 0.33; Std. ß = -0.109; p = 0.014). High salt intake in White, but not in black adults, were related to metabolomic changes and may contribute to pathophysiological mechanisms associated with increased BP.

THE EFFECTS OF Syzygium aromaticum-DERIVED TRITERPENES ON GASTROINTESTINAL GHRELIN EXPRESSION IN STREPTOZOTOCIN-INDUCED DIABETIC RATS.

BACKGROUND: Diabetic polyphagia has been associated with elevated plasma ghrelin levels in experimental type 1 diabetes. This increase in food consumption contributes to chronic hyperglycaemia in diabetes thus contributing to the development of micro- and macrovascular complications. We have reported that plant-derived oleanolic acid (OA) and maslinic acid (MA) reduce blood glucose levels, in part, through the inhibition of intestinal carbohydrate hydrolyzing enzymes and glucose transporters. However, their effects on food intake and plasma ghrelin concentrations are unclear. Accordingly, we investigated the effects of these triterpenes on food intake and ghrelin expression in streptozotocin-induced diabetic rats. MATERIAL: The effects of OA and MA on blood glucose concentration; food and water intake were monitored over five weeks after which plasma ghrelin concentrations were measured. Additionally, the expression of ghrelin in the various sections of the GIT was determined using Western blot analysis. RESULTS: Ghrelin concentrations in untreated STZ-induced diabetic rats were significantly higher in comparison to the non-diabetic control. Interestingly, the administration of OA and MA reduced food intake, blood glucose levels and plasma ghrelin levels in STZ-induced diabetic rats. This was further complemented by significant reductions in the gastrointestinal expression of ghrelin suggesting that the anti-diabetic properties of these triterpenes are mediated, in part, through the reduction of food intake and the modulation of ghrelin expression. CONCLUSION: The findings of the study suggest that the control of food intake through the reduction of ghrelin expression by plant-derived OA and MA may constitute an avenue of glycaemic control in diabetes mellitus.