Analysis of polar lipids in the serum from rats fed shiitake by liquid chromatography-mass spectrometry/mass spectrometry

A multilaboratory validation study of LC/MS biomarker assays for three lysophosphatidylcholines

Aim: Although the fit-for-purpose approach has been proposed for validation procedures and acceptance criteria for biomarker assays, practical biomarker assays to facilitate clinical application and regulatory documents on biomarker assays remain limited. Materials & methods: We assigned six independent laboratories and selected three lysophosphatidylcholines (LPCs): LPC(16:0), LPC(18:0) and LPC(18:1) as model biomarkers. Using LC-MS, the following key validation parameters were evaluated: calibration curve, carryover, parallelism, precision and relative accuracy and these values were similar among all laboratories. Further, we determined LPC levels in six lots of rat plasma at unknown concentrations and compared them among the laboratories. Conclusion: Our multilaboratory validation and reproducibility data are useful for the development of future biomarker assay validation procedures, as well as regulatory documents.

Chronic Effect of a Cafeteria Diet and Intensity of Resistance Training on the Circulating Lysophospholipidome in Young Rats

The daily practice of physical exercise and a balanced diet are recommended to prevent metabolic syndrome (MetS). As MetS is a multifactorial disorder associated with the development of serious diseases, the advancement of comprehensive biomarkers could aid in an accurate diagnosis. In this regard, it is known that gut microbiota is altered in MetS, and especially, lipid metabolites species are highly modified, thus emerging as potential biomarkers. In preliminary studies, we observed that alterations in serum lysoglycerophospholipids (Lyso-PLs) were shared between animals with diet-induced MetS and those performing resistance exercises assiduously. Therefore, our objective was the targeted determination of the lysophospholipidome in young rats fed a standard (ST) or a cafeteria diet (CAF) and submitted to different training intensities to evaluate its potential as a biomarker of a detrimental lifestyle. Targeted metabolomics focused on lysophosphatidylcholines (Lyso-PCs) and lysophosphatidylethanolamines (Lyso-PEs) and multivariate statistics were used to achieve an integral understanding. Chronic intake of CAF altered the serological levels of both lipid subclasses. Twenty-two Lyso-PLs were significantly altered by CAF, from which we selected Lyso-PCs (14:0), (17:1) and (20:2) and Lyso-PEs (18:2) and (18:3) as they were enough to achieve an optimal prediction. The main effect of physical training was decreased Lyso-PEs levels with disparities among training intensities for each diet. We concluded that an examination of the lysophospholipidome reveals the general state of the metabolome in young female rats, especially due to intake of an MetS-inducing diet, thus highlighting the importance of this family of compounds in lipid disorders.

Diets Containing Shiitake Mushroom Reduce Serum Lipids and Serum Lipophilic Antioxidant Capacity in Rats

BACKGROUND

We previously reported that dietary intake of shiitake mushroom (SM; Lentinus edodes) decreased serum concentrations of polar lipids in male rats.

OBJECTIVE

This study evaluated the dietary effects of SM on serum cholesterol-related and serum antioxidant indexes in rats of both sexes.

METHODS

Sprague-Dawley rats [38 dams and their offspring (20 males and 20 females/diet)] were fed diets containing 0 (control), 1%, 4%, or 10% (wt:wt) SM powder from gestation day 4 through to postnatal day (PND) 126. Biochemical indexes were monitored during the midgrowth phase (PNDs 50-66).

RESULTS

The food consumption by offspring fed the control diet and diets supplemented with SM was not different when measured on PND 65. However, the 4% and 10% SM diets resulted in male rats with 7% lower body weights than those of the other 2 groups on PND 66. SM consumption dose-dependently decreased the concentrations of lipidemia-related factors in sera, irrespective of sex. At PND 50, serum concentrations of total cholesterol, HDL cholesterol, and non-HDL cholesterol in SM-fed male and female rats were generally lower (3-27%) than those in the corresponding control groups. Consumption of the 10% SM diet resulted in significantly decreased (55%) serum triglyceride concentrations relative to the control groups for both sexes. The 10% SM diet elicited a 62% reduction of serum leptin concentrations in females but not in males, and this same diet increased serum insulin (137%) and decreased serum glucose (15%) in males compared with controls. Serum lipophilic antioxidant capacity in males and females fed SM diets was generally lower (31-86%) than that in the control groups.

CONCLUSION

SM decreased the concentrations of lipidemia-related factors in rat sera irrespective of sex. The SM-elicited reduction of lipophilic antioxidant capacity irrespective of sex may reflect a lower pro-oxidative state and, hence, improved metabolic profile.

2-Polyunsaturated acyl lysophosphatidylethanolamine attenuates inflammatory response in zymosan A-induced peritonitis in mice

In the present study, the anti-inflammatory action of lysophosphatidylethanolamine (lysoPtdEtn), orally administered, in zymosan A-induced peritonitis was examined. Oral administration of 2-DHA-lysoPtdEtn (ED(50), ~111 μg/kg) or 2-ARA-lysoPtdEtn (ED(50), 221 μg/kg) was found to inhibit the plasma leakage in mice treated with zymosan A. In support of this, 2-polyunsaturated acyl-lysoPtdEtn diminished the formation of LTC(4), a lipid mediator responsible for vascular permeability. Next, 2-DHA-lysoPtdEtn (ED(50), 110 μg/kg) or 2-ARA-lysoPtdEtn (ED(50), 123 μg/kg) effectively inhibited the leukocyte extravasation into the peritoneum. Consistent with this, each polyunsaturated-lysoPtdEtn diminished the formation of LTB(4) and 12-HETE, potent chemotactic factors. Additionally, the level of pro-inflammatory mediator (IL-1 β, IL-6, TNF-α or NO) was lowered remarkably in contrast to the augmentation of anti-inflammatory interleukin IL-10. Furthermore, 2-(15-HETE)-lysoPtdEtn and 2-(17-HDHE)-lysoPtdEtn, 15-lipoxygenation product of 2-ARA-lysoPtdEtn and 2-DHA-lysoPtdEtn, respectively, were more potent than corresponding lysoPtdEtn, suggesting the action of 2-acyl-lysoPtdEtn might be expressed through 15-lipoxygenation. In support of this, the formation of 15-HETE and LXA(4) was upgraded in accordance with an increasing dose of 2-ARA-lysoPtdEtn. Separately, anti-inflammatory actions, 2-polyunsaturated acyl-lysoPtdEtns also drastically diminished leukocyte infiltration in a later phase of zymosan A-induced peritonitis, indicating that these lipids also possess pro-resolving activity. Taken together, it is suggested that polyunsaturated lysoPtdEtns and their lipoxygenation derivatives, could be classified as potent anti-inflammatory lipids.