[Métodos] CSE and CHE from Coffea Arabica were obtained as described in patent WO/2013/004873. Experiments were carried out using human proximal tubular cells (HK2) as a model of DN induced by high concentrations of glucose, fructose (25 mM) and the uremic toxin Indoxyl Sulphate (IS). The effect of extracts on intracellular ROS release of treated cells was studied by measuring the fluorescence intensity of the 21,71-dichloro-dihydro-fluorescein diacetate (DCFH-DA) probe, which is proportional to the amount of ROS formed. Nitric oxide assay was performed in order to evaluate the anti-inflammatory properties of samples. Furthermore, the expression of inflammatory genes (TNFα, CCL2 and NLRP3) was quantified by Real Time – PCR.

[Introducción] A high intake of dietary sugar is associated to an increased risk of diabetes and its complications, such as diabetic nephropathy (DN). Fifty percent of individuals with longtime diabetes usually develop renal damage during their lifetime. An increase in oxidative stress-derived inflammation is a major mechanism in the pathogenesis of DN. Coffee silverskin extract (CSE) (WO/2013/004873) and coffee husk extract (CHE), two coffee by-products, possess high antioxidant power and may present anti-inflammatory effect and, as a consequence, potential for reducing the risk of DN. No previous studies on the anti-inflammatory effect of such extracts are available.

[Resultados] High concentrations of glucose and fructose (25 mM) in combination with IS (1 mM) had a significant effect on the studied biomarkers in HK2 cells. CSE and CHE significantly decreased (p<0.05) ROS formation in treated cells to the basal levels observed for control cells. Pre-treatment of LPS-stimulated macrophages with CSE and CHE (0.1 and 1 mg/ml) significantly decreased (p<0.05) the production of nitric oxide, showing the potential of these by-products as an antiinflammatory agents. CSE and CHE significantly reduced (p<0.05) the expression of TNFα, NLRP3 and CCL2 when it was induced by IS and high concentrations of glucose or fructose (25 mM).

[Conclusiones] Obtained results suggest that coffee by-product extracts represent a natural source of antioxidant for the inhibition of intracellular ROS formation. Data on ROS and NO production are in line with those observed by gene expression analysis of TNFα, NLRP3 and CCL2. Although in vivo studies should be conducted, data suggest that coffee by-product extracts may be antioxidant and anti-inflammatory agents with potential therapeutic effects in DN.

[Discusión] ROS are implicated in the pathological signaling of DN and regulate inflammation by activating TNFα, iNOS, which increases levels of NO, CCL-2 and NLRP-3. Intake of antioxidant natural extracts is associated to the prevention of diabetes and its complications.

[Obejtivos] To obtain novel data on the anti-inflammatory and antioxidant effect of CSE and CHE, on a human kidney cell model of DN induced by high sugar concentrations, using cellular biomarkers and gene expression analysis.

Trabajo presentado al XII Congreso Internacional Nutrición, Alimentación y Dietética, celebrado en Madrid el 11 y 12 de abril de 2018.

This work was funded by MINECO(AGL2014-57239-R, BES2015-072191).

Peer reviewed