EPA and DHA containing phospholipids have contrasting effects on membrane structure

Omega-3 FAs EPA and DHA influence membrane fluidity, lipid rafts, and signal transduction. A clinical trial, Reduction of Cardiovascular Events with Icosapent Ethyl—Intervention Trial, demonstrated that high-dose EPA (4 g/d icosapent ethyl) reduced composite cardiovascular events in statin-treated high-risk patients. EPA benefits correlated with on-treatment levels, but similar trials using DHA-containing formulations did not show event reduction. We hypothesized that differences in clinical efficacy of various omega-3 FA preparations could result from differential effects on membrane structure. To test this, we used small-angle X-ray diffraction to compare 1-palmitoyl-2-eicosapentaenoyl-sn-glycero-3-phosphocholine (PL-EPA), 1-palmitoyl-2-docosahexaenoyl-sn-glycero-3-phosphocholine (PL-DHA), and 1-palmitoyl-2-arachidonoyl-sn-glycero-3-phosphocholine (PL-AA) in membranes with and without 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) and cholesterol. Electron density profiles (electrons/ų vs. Å) were used to determine membrane structure, including membrane width (d-space). PL-EPA and PL-DHA had similar membrane structures without POPC and/or cholesterol but had contrasting effects in the presence of POPC and cholesterol. PL-EPA increased membrane hydrocarbon core electron density over an area of ±0–10 Å from the center, indicating an extended orientation. PL-DHA increased electron density in the phospholipid head group region, concomitant with disordering in the hydrocarbon core and a similar d-space (58 Å). Adding equimolar amounts of PL-EPA and PL-DHA produced changes that were attenuated compared with their separate effects. PL-AA increased electron density centered ±12 Å from the membrane center. The contrasting effects of PL-EPA, PL-DHA, and PL-AA on membrane structure may contribute to differences observed in the biological activities and clinical actions of various omega-3 FAs.

Mineral oil: safety and use as placebo in REDUCE-IT and other clinical studies

Mineral oil is often used as a clinical trial placebo. Pharmaceutical-grade mineral oil consists of a mixture of saturated hydrocarbons, with a purity and chemical structure that differs substantially from food-grade or technical-/industrial-grade mineral oils. Interest in mineral oil was piqued by suggestions that a portion of the substantially positive results of the Reduction of Cardiovascular Events with Icosapent Ethyl-Intervention Trial (REDUCE-IT) might be attributable to the theoretical negative effects of mineral oil rather than being due to the clinical benefits of icosapent ethyl. The objective of this review was to explore possible mineral oil safety and efficacy effects and contextualize these findings in light of the REDUCE-IT conclusions. A literature search identified studies employing mineral oil placebos. Eighty studies were identified and relevant data extracted. Adverse events associated with mineral oil were generally gastrointestinal and consistent with use as a lubricant laxative. Changes in triglycerides, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, high-sensitivity C-reactive protein, and other biomarkers were inconsistent and generally not statistically significant, or clinically meaningful with mineral oil, as were changes in blood pressure. There was no consistent evidence that mineral oil in the amounts used in the REDUCE-IT or Effect of Vascepa on Progression of Coronary Atherosclerosis in Patients With Elevated Triglycerides on Statin Therapy (EVAPORATE) trials affects absorption of essential nutrients or drugs, including statins. These results were then considered alongside publicly available data from REDUCE-IT. Based on available evidence, mineral oil does not appear to impact medication absorption or efficacy, or related clinical outcomes, and, therefore, does not meaningfully affect study conclusions when used as a placebo at the quantities used in clinical trials.

Impact of combined (18)F-FDG PET/CT in head and neck tumours

To compare the interobserver agreement and degree of confidence in anatomical localisation of lesions using 2-[fluorine-18]fluoro-2-deoxy-D-glucose (¹⁸F-FDG) positron emission tomography (PET)/computed tomography (CT) and ¹⁸F-FDG PET alone in patients with head and neck tumours. A prospective study of 24 patients (16 male, eight female, median age 59 years) with head and neck tumours was undertaken. ¹⁸F-FDG PET/CT was performed for staging purposes. 2D images were acquired over the head and neck area using a GE Discovery LS™ PET/CT scanner. ¹⁸F-FDG PET images were interpreted by three independent observers. The observers were asked to localise abnormal ¹⁸F-FDG activity to an anatomical territory and score the degree of confidence in localisation on a scale from 1 to 3 (1=exact region unknown; 2=probable; 3=definite). For all ¹⁸F-FDG-avid lesions, standardised uptake values (SUVs) were also calculated. After 3 weeks, the same exercise was carried out using ¹⁸F-FDG PET/CT images, where CT and fused volume data were made available to observers. The degree of interobserver agreement was measured in both instances. A total of six primary lesions with abnormal ¹⁸F-FDG uptake (SUV range 7.2–22) were identified on ¹⁸F-FDG PET alone and on ¹⁸F-FDG PET/CT. In all, 15 nonprimary tumour sites were identified with ¹⁸F-FDG PET only (SUV range 4.5–11.7), while 17 were identified on ¹⁸F-FDG PET/CT. Using ¹⁸F-FDG PET only, correct localisation was documented in three of six primary lesions, while ¹⁸F-FDG PET/CT correctly identified all primary sites. In nonprimary tumour sites, ¹⁸F-FDG PET/CT improved the degree of confidence in anatomical localisation by 51%. Interobserver agreement in assigning primary and nonprimary lesions to anatomical territories was moderate using ¹⁸F-FDG PET alone (kappa coefficients of 0.45 and 0.54, respectively), but almost perfect with ¹⁸F-FDG PET/CT (kappa coefficients of 0.90 and 0.93, respectively). We conclude that ¹⁸F-FDG PET/CT significantly increases interobserver agreement and confidence in disease localisation of ¹⁸F-FDG-avid lesions in patients with head and neck cancers.

Molecular and cellular evidence for an oligodendrocyte abnormality in schizophrenia

Our previous analyses in postmortem prefrontal cortex samples from a well-characterized cohort of severely affected schizophrenics and in matched controls demonstrated decreased expression of myelin and oligodendrocyte-related genes in the disease state. This decreased expression, now replicated in independent studies, suggests that there is a disruption of oligodendrocyte function and/or a loss of oligodendrocytes in schizophrenia. In the current report, we review expression studies in schizophrenia and present data demonstrating consistently fewer oligodendrocytes in schizophrenics compared to controls. The decrease in density reached 22% (p < 0.01) in layer III of area 9 and 20% (p < 0.02) in the white matter of the superior frontal gyrus. These data, when taken together with expression studies carried out by us and by other groups, and by imaging and other microscopic studies, point to a major involvement of oligodendrocyte abnormalities in schizophrenia. Therapies modulating oligodendrocyte survival and differentiation may therefore be beneficial in schizophrenia.

Aromatherapy and behaviour disturbances in dementia: a randomized controlled trial

A random controlled trial of the relaxing effects of an aromatherapy massage on disordered behaviour in dementia was conducted. Twenty-one patients were randomly allocated into one of three conditions, aromatherapy and massage (AM), conversation and aromatherapy (CA) and massage only (M). AM showed the greatest reduction in the frequency of excessive motor behaviour of all three conditions. This reached statistical significance between the hours of three and four pm (p < 0.05). Post hoc analysis suggested that at this time of day the AM consistently reduced motor behaviour when compared with CA (p = 0.05). This provides preliminary evidence of a measurable sedative effect of aromatherapy massage on dementia within a robust scientific paradigm. Further research is recommended with an expanded sample size.