Propionate regulates lymphocyte proliferation and metabolism

• 1.1. The effect of propionate on lymphocyte proliferation and metabolism was investigated. Lymphocytes obtained from human blood and rat mesenteric lymph nodes were utilized.
• 2.2. Propionate at concentrations of 0.04 and 1.0 mmol/1 stimulated the amount of [³H]thymidine incorporated either in cultured human T lymphocytes or rat T and B lymphocytes.
• 3.3. Concentrations of propionate between 2 and 5 mmol/1 caused a marked inhibition of lymphocyte proliferation.
• 4.4. This short-chain fatty acid was metabolized by these cells and produced succinate in significant amounts; however, its oxidation was low.
• 5.5. Propionate did not alter glucose, glutamine and pyruvate utilization and oxidation in incubated rat lymphocytes but increased the formation of lactate and aspartate.
• 6.6. In contrast, propionate inhibited by 50% the synthesis of lymphocyte lipid from [1-¹⁴C]acetate at concentrations of 0.5 and I mmol/1 and reduced by half the incorporation of ³H₂O into lipids at 1 and 5 mmol/1.
• 7.7. The results suggest that inhibition of lipid synthesis is a possible mechanism leading to reduction of lymphocytes proliferation.