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White matter hyperintensities (WMH) are presumed to indicate subcortical ischemic vascular disease but their underlying pathobiology remains incompletely understood. The soluble epoxide hydrolase (sEH) enzyme converts anti-inflammatory and vasoactive cytochrome p450-derived polyunsaturated fatty acid epoxides into their less active corresponding diol species. Under the hypothesis that the activity of sEH might be associated with subcortical ischemic vascular disease and vascular cognitive impairment, this study aimed to compare the relative abundance of sEH substrates and products in peripheral blood between patients with extensive WMH (discovered due to transient ischemic attack; n = 29) and healthy elderly with minimal WMH (n = 25). The concentration of 12,13-DiHOME (a sEH-derived linoleic acid metabolite), and the ratio of 12,13-DiHOME to its sEH substrate, 12,13-EpOME, were elevated in the extensive WMH group (F1,53 = 5.9, p = 0.019), as was the 9,10-DiHOME/9,10-EpOME ratio (F1,53 = 5.4, p = 0.024). The 12,13-DiHOME/12,13-EpOME ratio was associated with poorer performance on a composite score derived from tests of psychomotor processing speed, attention, and executive function (β = - 0.473, p = 0.001, adjusted r2 = 0.213), but not with a composite verbal memory score. In a mediation model, periventricular WMH (but not deep WMH), explained 37% of the effect of the 12,13-DiHOME/12,13-EpOME ratio on the speed/attention/executive function composite score (indirect effect = - 0.50, 95% bootstrap confidence interval [- 0.99, - 0.17] Z-score units). Serum oxylipin changes consistent with higher sEH activity were markers of vascular cognitive impairment, and this association was partly explained by injury to the periventricular subcortical white matter.

Background Oleaginous fungi are efficient tools to convert agricultural waste streams into valuable components. The filamentous fungus Mucor circinelloides was cultivated in whey permeate, a byproduct from cheese production, to produce an oil-rich fungal biomass. Response surface methodology was used to optimize the fermentation conditions such as pH and temperature for increased biomass yield and lipid accumulation. Quantification and characterization of the fungal biomass oil was conducted. Results Upstream lactose hydrolysis of the whey permeate increased the biomass yield from 2.4 to 7.8 (g dry biomass/L) compared to that of non-hydrolyzed whey permeate. The combination of low pH (4.5) and pasteurization minimized microbial competition, thus favoring fungal growth. A central composite rotatable design was used to evaluate the effects of temperature (22.4–33.6 °C) and a lower pH range (3.6–4.7) on biomass yield and composition. The highest biomass yield and oil content was observed at high temperature (33.6 °C), while the pH range evaluated had a less pronounced effect. The predictive model was validated at the optimal conditions of 33.6 °C and pH 4.5. The fungal biomass yield plateaued at 9 g dry cell weight per liter, while the oil content and lipid yield reached a maximum of 24% dry biomass and 2.20 g/L, respectively, at 168 h. Triacylglycerides were the major lipid class (92%), which contained predominantly oleic (41%), palmitic (23%), linoleic (11%), and γ-linolenic acid (9%). Conclusions This study provided an alternative way of valorization of cheese whey permeate by using it as a substrate for the production of value-added compounds by fungal fermentation. The fatty acid profile indicates the suitability of M. circinelloides oil as a potential feedstock for biofuel production and nutraceutical applications. Electronic supplementary material The online version of this article (10.1186/s13036-018-0116-5) contains supplementary material, which is available to authorized users.