Elena Arranz

Gain-of-function mutations in complement factor B are associated with atypical hemolytic uremic syndrome

Hemolytic uremic syndrome (HUS) is an important cause of acute renal failure in children. Mutations in one or more genes encoding complement-regulatory proteins have been reported in approximately one-third of nondiarrheal, atypical HUS (aHUS) patients, suggesting a defect in the protection of cell surfaces against complement activation in susceptible individuals. Here, we identified a subgroup of aHUS patients showing persistent activation of the complement alternative pathway and found within this subgroup two families with mutations in the gene encoding factor B (BF), a zymogen that carries the catalytic site of the complement alternative pathway convertase (C3bBb). Functional analyses demonstrated that F286L and K323E aHUS-associated BF mutations are gain-of-function mutations that result in enhanced formation of the C3bBb convertase or increased resistance to inactivation by complement regulators. These data expand our understanding of the genetic factors conferring predisposition to aHUS, demonstrate the critical role of the alternative complement pathway in the pathogenesis of aHUS, and provide support for the use of complement-inhibition therapies to prevent or reduce tissue damage caused by dysregulated complement activation.

Comparison of antioxidant activities of bovine whey proteins before and after simulated gastrointestinal digestion

Oxidative stress caused by free radicals has been implicated in several human disorders. Dietary antioxidants can help the body to counteract those reactive species and reduce oxidative stress. Antioxidant activity is one of the multiple health-promoting attributes assigned to bovine whey products. The present study investigated whether this activity was retained during upper gut transit using a static simulated in vitro gastrointestinal digestion (SGID) model. The capacity to scavenge free radicals and reduce ferric ion of whey protein isolate (WPI), individual whey proteins, and hydrolysates pre- and post-SGID were measured and compared using various antioxidant assays. In addition, the free AA released from individual protein fractions in physiological gut conditions were characterized. Our results indicated that the antioxidant activity of WPI after exposure to the harsh conditions of the upper gut significantly increased compared with intact WPI. From an antioxidant bioactivity viewpoint, this exposure negates the need for prior hydrolysis of WPI. The whey protein α-lactalbumin showed the highest antioxidant properties post-SGID (oxygen radical absorbance capacity = 1,825.94 ± 50.21 μmol of Trolox equivalents/g of powder) of the 4 major whey proteins tested with the release of the highest amount of the antioxidant AA tryptophan, 6.955 μmol of tryptophan/g of protein. Therefore, α-lactalbumin should be the preferred whey protein in food formulations to boost antioxidant defenses.

Winemaking by-products as anti-inflammatory food ingredients

ABSTRACT The anti-inflammatory potential of grape stem (GTE) and grape seed extracts (GSE) obtained by pressurized liquid extraction (PLE) was tested in vitro using THP-1 human macrophage cells (THP-1/M). THP-1/M were activated by lipopolysaccharide (LPS) or human ox-LDL and the cytokine secretion (TNF-α, IL-1β, IL-6 and IL-10) was evaluated. Results indicated that both GTE and GSE, at 10 µg/mL, markedly suppressed the production of pro-inflammatory cytokines when THP-1/M were activated with human ox-LDL. However, when LPS was used to activate THP-1/M, only GTE was able to decrease IL-6 production. HPLC analysis of extracts indicated that GSE presented a high amount of proantocyanidins, which have been described as anti-inflammatory agents. Meanwhile, GTE contained an important quantity of trans-resveratrol and quercetin derivatives, components which also presented a high anti-inflammatory activity. These results increased the added value of winemaking by products as a source of natural anti-atherogenic ingredients.

Pressurized liquids as an alternative green process to obtain anti-inflammatory agents from rosemary, marjoram and basil

Inflammation response protects the host against tissue injury and microbial invasion. As such, this response should be short-lived, and failing can result in pathogenesis of many immunity-related diseases. The aim of this work was to study the anti-inflammatory activity of different pressurized liquid extract (PLE) obtained from Rosmarinus officinalis, Origanum majorana and Ocimum basilicum. PLE is a technique based on the extraction at temperature and pressure high enough to maintain the solvent in a liquid state during the whole extraction procedure. To determinate the optimal antioxidant extract were used different extraction conditions and that was obtained as follows: 50% ethanol: 50% water as solvent, 150 C as extraction temperature and 10 minutes as static time. THP-1 macrophages activated by lipopolysaccharide (LPS) (0.05mg/mL) or human oxidized-LDL (ox-LDL) (75mg/mL) were treated with 10, 15 and 25mg/mL of extracts during 24 hours. The secretion and gene expression of several inflammatory mediators (TNF-a, IL-1b, IL-6 and IL-10) was measured with ELISA kits and relative quantification in qPCR respectively. All experiments were made with three biological replicates. Rosemary extract was the most active, since 10mg/mL of this extract reduce the secretion of TNF-a, IL-1b and IL-6, proinflammatory cytokines, in cells activated with LPS or oxLDL. Although in cells activated with ox-LDL, this reduction was highest in IL-1b secretion. Also marjoram and basil reduced the secretion of the analyzed proinflammatory cytokines but less than rosemary. Using 25mg/mL of marjoram or basil the secretion of TNF-a was reduced until 25% while the same amount of rosemary reduced it until 80% in cells activated with LPS because in cells activated with ox-LDL there was less difference. In either case were found significant differences in IL-10 secretion, an anti-inflammatory cytokine. The results obtained in gene expression also showed a decrease in proinflammatory cytokines, being more pronounced in the case of rosemary, corroborating what was obtained in the measurement of the secretion. In conclusion, this technique could be used as an alternative green process to obtained extracts with an important anti-inflammatory activity. Thus rosemary, marjoram and basil pressurized liquid extract could be proposed as a food ingredients with anti-inflammatory properties.