In their previous study, the researchers reported that tacrolimus (Tac), an immunosuppressive drug commonly used after organ transplantation, does not reduce Th17 response after kidney transplantation. They, therefore, decided to look for a complementary treatment that can increase its efficacy. The researchers settled on resveratrol, a known polyphenol with various biological activities. Recent studies suggest that this compound has immune-modulating effects in various immune diseases that rely on Th17.
Under Tac-treatment conditions, the researchers evaluated the effects of resveratrol on CD4+ T cell differentiation to Th17 cells in peripheral blood mononuclear cells (PBMCs). They also examined its effects on the proliferation of CD4+ T cells co-cultured with human renal proximal tubular epithelial cells (HRPTEpiCs). Additionally, they used a murine skin transplant model to test the effects of resveratrol on Th17 cells.
The researchers reported that in PBMCs -- the major cells involved in human immunity -- treatment with a combination of Tac and resveratrol suppressed Th17 immune response. In the co-culture study, the same combination significantly decreased HRPTEpiC-induced T cell proliferation.
Meanwhile, resveratrol treatment in Jurkat cells -- immortalized T lymphocyte (white blood cells) cell line -- also induced AMP-activated protein kinase (AMPK) expression but suppressed mammalian target of rapamycin (mTOR) expression. AMPK is an enzyme that regulates cellular metabolism while mTOR is a signaling molecule that regulates a wide range of cellular functions, such as transcription, translation, growth, survival, and differentiation. The inhibition of mTOR meant that resveratrol could block the Th17 pathway.
On the other hand, the combination of Tac and resveratrol also significantly prolonged skin graft survival and suppressed Th17 cells in the murine skin transplant model. (Related: Resveratrol is "Nature's Medicine" for Cancer, Heart Disease and Much More.)
Based on these results, the researchers concluded that resveratrol provides additional immunosuppressive effects to Tac by suppressing effector CD4+ T cells, especially Th17 cells. Thus, it can be used to prevent adverse immune responses after organ transplantation.
Aside from red and purple grapes, resveratrol can be found in a variety of natural sources, such as blueberries, cranberries, mulberries, lingonberries, peanuts, and pistachios. It is also present in abundance in the roots of Japanese knotweed, a perennial plant used in traditional medicine. Resveratrol is a phytoalexin, a chemical that plants produce to fight off pathogenic microbes. Some plants also produce resveratrol to withstand drought and cope with the lack of nutrients. In higher organisms, resveratrol is known to provide several health benefits, including:
Resveratrol is a phytonutrient that promotes good health and could help people live longer. If you wish to take advantage of its wonderful effects, add resveratrol-rich foods to your diet instead of taking resveratrol supplements. Couple your diet with regular exercise and smart lifestyle choices to boost your health and make the most of resveratrol's health benefits.