Renal and Extrarenal Effects of Gum Arabic ( Acacia Senegal ) - What Can be Learned from Animal Experiments?

Abstract

Gum arabic (GA), a water-soluble dietary fiber rich in Ca²⁺, Mg²⁺ and K⁺, is used in Middle Eastern countries for the treatment of patients with chronic kidney disease. Recent animal experiments shed some light into mechanisms involved in the therapeutic action of GA. According to experiments in healthy mice, GA treatment increases creatinine clearance, enhances renal excretion of ADH, Mg²⁺ and Ca²⁺, decreases plasma phosphate concentration as well as urinary excretion of phosphate and Na⁺. In diabetic mice GA treatment increases urinary Ca²⁺ excretion, and decreases plasma phosphate concentration, plasma urea concentration, urinary flow rate, natriuresis, phosphaturia, glucosuria, proteinuria as well as blood pressure. Extrarenal effects of GA treatment in mice include decreased expression of intestinal Na⁺ coupled glucose carrier SGLT1 with subsequent delay of electrogenic intestinal glucose transport, glucose-induced hyperglycemia, hyperinsulinemia and body weight gain. GA treatment decreases colonic transcription of the angiogenetic factors angiogenin 1, angiogenin 3 and angiogenin 4, of CD38 antigen, aquaporin4, interleukin18, vav-3-oncogene, y⁺-amino acid-transporter, sulfatase1, ubiquitinD and chemokine ligand5. Moreover, GA treatment decreases angiogenin and ß-catenin protein expression. Accordingly, GA treatment counteracts the development of tumors following chemical cancerogenesis. In mouse dendritic cells, antigen-presenting cells linking innate and adaptive immunity, GA treatment modifies maturation and cytokine release. GA treatment further favourably influences the course of murine malaria. The effects of GA treatment on plasma phosphate concentration, blood pressure and proteinuria may prove beneficial in chronic renal failure and diabetic nephropathy. The effect of GA on intestinal glucose transport may be useful in the prophylaxis and treatment of obesity and diabetes, the effect of GA on angiogenin and ß-catenin expression could be exploited for the prophylaxis against colon carcinoma, the effects of GA on angiogenin expression and dendritic cells may be useful in the treatment of inflammatory disease and malaria.