Rapid method for the analysis of red blood cell fatty acids by reversed-phase high-performance liquid chromatography

Separation and Determination of Fatty Acids from Lipid Fractions by High-Performance Liquid Chromatography: Cholesterol Esters of Umbilical Cord Arteries

Preeclampsia is accompanied by an extensive remodeling of the extracellular matrix of umbilical cord. It is associated with an increase in collagen content in the umbilical cord artery. Furthermore, preeclampsia distinctly reduces proteolytic and gelatinolytic activity, especially after activation with various agents.

We decided to develop a method for separation and determination of fatty acids from different tissues by high-performance liquid chromatography. That method allowed us to determine cholesteryl ester composition and content in umbilical cord arteries. Studies were performed on the umbilical cord arteries taken from 10 newborns delivered by healthy mothers and 10 newborns delivered by mothers with preeclampsia. Cholesteryl esters were isolated by thin layer chromatography. Fatty acids were liberated by basic hydrolysis and analyzed by HPLC of their p-bromophenacyl derivatives using detection at 254 nm. It was found that saturated fatty acids were the main group of fatty acids incorporated to cholesteryl esters in all control and preeclamptic umbilical cord arteries. Preeclampsia caused a significant increase in cholesteryl ester content in the umbilical cord arteries. An increase of neutral lipid content in vessel walls of newborns delivered by mothers with preeclampsia may be one of the factors that evoke the initiation of hypertension in utero and its amplification throughout childhood and adult life. The described method reduces time and cost consumption and allows us to determine almost all fatty acids forming cholesteryl esters contained in the tissue sample.

Lipid compounds of the umbilical cord vein and their alterations in preeclampsia

The lipid composition of vascular walls changes during development, ageing and pathological processes. Preeclampsia is the most common pregnancy-associated pathological syndrome. It is accompanied by significant remodelling of the extracellular matrix, both in the umbilical cord vessels and in the surrounding Wharton's jelly. Lipids of the umbilical cord have not been extensively studied. Here we evaluate the lipid composition of the umbilical cord vein and its alteration in preeclampsia. Thin layer chromatography and high-performance liquid chromatography were employed for these analyses. It was found that the umbilical cord vein wall, as with most human tissues, contains free fatty acids, mono-, di- and triacylglycerols, free cholesterol and its esters. The characteristic feature is the presence of high amounts of monounsaturated fatty acids, mainly myristoleic acid (C14:1) and oleic acid (C18:1), and polyunsaturated fatty acids, including eicosapentaenoic acid (C20:5) and docosahexaenoic acid (C22:6), which are rather minor lipid components of most human tissues. They exist both in a free form and in a form of acylglycerols and cholesterol esters. Preeclampsia is associated with an increase in the accumulation of free fatty acids, acylglycerols and cholesterol esters in the umbilical cord vein wall, with a proportional reduction in unsaturated fatty acid contents in all the investigated lipid fractions. Total amount of myristoleate was similar to control values. It is suggested that stimulation of lipolysis in maternal tissues increases supply of free fatty acids to foetal blood and promotes the accumulation fatty acids and their esters in some foetal vascular walls.

Fatty acid composition of triacylglycerols from Wharton's jelly determined by high-performance liquid chromatography

The improved method for HPLC determination of fatty acids was proposed. The chromatographic separation of p-bromophenacyl derivatives of fatty acids under a gradient elution was achieved at 40 degrees C with an RP-18 LiChroCART 5 column and organic mobile phase containing methanol, acetonitrile, water and TEAP buffer pH 5.6. The quantitative determination of those derivatives was performed at 254 nm. Preeclampsia, the most common pregnancy complication, did not affect triacylglycerol content in the umbilical cord Wharton's jelly in comparison to the control material. However, it changed the composition of fatty acids, bound to that lipid class. The method allows the determination of almost all fatty acids forming the investigated neutral lipid class, contained in a solid tissue sample. The use of TEAP buffer excluded precipitation and flow stoppage in the HPLC system. The method reduced time and costs and might be useful for all other lipid classes and different tissues.

Influencing the immune parameters in germ-free piglets by administration of seal oil with increased content of omega-3 PUFA

Oral administration of oil with an increased content of omega-3 polyunsaturated fatty acids to germ-free piglets resulted in a significant increase in the total values of CD4, CD8 lymphocytes, B lymphocytes, and monocytes, in peripheral blood in comparison with the controls. The metabolic activities of phagocytes as well as the polyclonal activation of lymphocytes were not significantly influenced. The level of growth factor was significantly higher, as determined on the basis of somatomedin in the blood serum. Biochemical indices showed a significant increase in the level of eicosapentaenoic and docosahexaenoic acids in blood serum and the decrease in the level of arachidonic acid at the same time.

High-performance liquid chromatographic determination of mono-, poly- and hydroxycarboxylic acids in foods and beverages as their 2-nitrophenylhydrazides

The application of direct derivatization in conjunction with high-performance liquid chromatography (HPLC) is described for the determination of both free and total carboxylic acids in foods and beverages. The method is based on the reaction of the carboxylic acids with 2-nitrophenylhydrazine hydrochloride, without complicated isolation steps, which produces their non-volatile hydrazine derivatives. The HPLC of a series of carboxylic acid groups was performed isocratically with short retention times. The analytical results showed good recovery and reproducibility using each internal standard. Due to its excellent selectivity and sensitivity, the present method can serve as a useful tool for routine determinations of mono-, poly- and hydroxycarboxylic acids in foods and beverages.

Use of derivatization to improve the chromatographic properties and detection selectivity of physiologically important carboxylic acids

In this review, tagging techniques with reagents used for ultraviolet-visible (UV-Vis), fluorescent (FL), chemiluminescent (CL) and electrochemical detection (ED) for higher carboxylic acids in HPLC are evaluated in terms of the tagging reactions, handling, flexibility, stability of the reagents and the corresponding derivatives, sensitivity and selectivity. Emphasis is given to the applications of these tagging techniques to biologically important carboxylic acids of relatively high molecular mass including free fatty acids, prostaglandins, leukotrienes and thromboxanes etc. Some typical examples are described. Although RIA and GC-MS are powerful techniques for the highly sensitive determination of carboxylic acids, tagging for these techniques is not included in this review because recent progress in tagging methods has been mainly concerned with HPLC detection.

High-performance liquid chromatographic analysis of fatty acid compositions of platelet phospholipids as their 2-nitrophenylhydrazides

A novel high-performance liquid chromatographic method for biologically important fatty acids incorporated into platelet phospholipids in esterified form has been developed. 2-Nitrophenylhydrazine hydrochloride was used as a pre-column labelling agent to convert the saponified platelet phospholipids directly into corresponding fatty acid hydrazides, without a complicated isolation procedure. Isocratic separation was achieved within only 36 min for twenty-five saturated and mono- and polyunsaturated fatty acids (C8:0-C22:6), including cis and trans isomers, on a YMC-FA column. The analytical results showed good quantitative accuracy. Fatty acid compositions were determined in platelet phospholipids obtained from normal subjects and patients with diabetes mellitus. The method is simple, rapid and adequate for labelling esterified fatty acids in biological materials, and has several advantages with regard to resolution, analysis time and sensitivity over previously published methods.