The fatty acid composition of phospholipids of spermatozoa from infertile patients (original) (raw)
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Membrane fluidity and lipid content of human spermatozoa selected by swim-up method
International Journal of Andrology, 2001
In this work, we examined whether spermatozoa (spz) from normospermic fertile patients and selected by a swim-up (S-U) procedure had a particular membrane¯uidity related to their maturity and their lipid content as compared with the sperm cells from the whole ejaculate (total sperm). Swim-up selected sperm had a reduced cytoplasmic space as revealed by a lower creatine kinase (CK) activity compared with total sperm (2 1 vs. 12 5 mUI/10 7 spz, p < 0.05). The cholesterol (Chol) and total phospholipid (PL) contents were signi®cantly lower in S-U selected sperm than in total sperm (0.72 0.08 vs. 1.20 0.30 nmol/10 6 spz for Chol and 1.77 0.17 vs. 2.78 0.50 nmol/10 6 spz for PL, p < 0.05) and such a decrease was observed for the three major membrane PL: phosphatidylethanolamine (PE), phosphatidylcholine (PC) and sphingomyelin (SM). However, these decreases were not associated with a change in either Chol/PL or PC/(PC + PE) molar ratios. Membrane¯uidity estimated bȳ uorescence polarization remained comparable between the S-U sperm fraction and total sperm (¯uorescence polarization anisotropy, r, which is inversely proportional to thē uidity: 0.235 0.006 vs. 0.230 0.005). The sperm membrane¯uidity obtained in normospermic patients was compared with abnormospermic ones (oligoasthenoteratospermia). In abnormospermic patients, the membrane¯uidity was decreased in migrated spermatozoa compared with total sperm (anisotropy: 0.210 0.010 vs. 0.250 0.013, p < 0.01). Our data suggest that the S-U method selected a subpopulation of mature spermatozoa characterised by a low content of Chol and PL, likely related to a reduced membrane area. The fact that Chol/PL and PC/(PC + PE) molar ratios were unchanged shows a maintenance of the membrane quality. This was con®rmed by the¯uorescence anisotropy measurement showing no difference in plasma membrane¯uidity between S-U selected sperm and total sperm. In abnormal semen the migrated spermatozoa had a lower¯uidity compared with total sperm suggesting a defective sperm function. These results bring new elements characterizing the S-U selected spermatozoa.
Prostaglandins, leukotrienes, and essential fatty acids, 2007
The lipid composition of the sperm membrane has a significant effect on the functional characteristics of spermatozoa. In the present study, fatty acid composition of spermatozoa and seminal plasma levels of free 15-F(2t)-Isoprostane and catalase were assayed in men with normozoospermia, asthenozoospermia, asthenoteratozoospermia, and oligoasthenoteratozoospermia. In spermatozoa from asthenozoospermic men only oleic acid levels showed a significant difference from normozoospermic men. In spermatozoa from asthenoteratozoospermic and oligoasthenoteratozoospermic samples all of the tested fatty acids were significantly higher than those from normozoospermic samples. Seminal plasma levels of catalase were significantly lower in all patients while levels of free 15-F(2t)-Isoprostane were significantly higher in all patients compared with normozoospermic men. Spermatozoa from pathological samples may have higher levels of polyunsaturated fatty acids, especially docosahexaenoic acid (DHA),...
Avicenna Journal of Medical Biochemistry, 2014
Background: Lipids play an important role in the functional activity of sperm cells. Objectives: The main goal of this study was to assess the correlation between the levels of cholesterol, phospholipids and triacylglycerols found in serum, with the lipid levels of semen in infertile men. Patients and Methods: Cholesterol, phospholipids and triacylglycerols in sperm cells, seminal plasma and serum were assayed in 60 infertile men. Results: There were no significant relationships between the concentration of sperm and seminal plasma cholesterol with serum cholesterol (r = 0.003, P = 0.9 and r = 0.055, P = 0.67, respectively), between the concentration of sperm and seminal plasma triglycerides with serum triglycerides (r = 0.16, P = 0.2 and r =-0.039, P = 0.77, respectively), or between the concentration of sperm and seminal plasma phospholipids with serum phospholipids (r = 0.18, P = 0.16 and r = 0.053, P = 0.69, respectively). Conclusions: These results suggest that serum cholesterol, phospholipids and triacylglycerols have no effect on the levels of cholesterol, phospholipids and triacylglycerols of spermatozoa and seminal plasma. Our findings suggest that sperm lipid content is regulated locally within the male reproductive tract.
Molecular Reproduction and Development, 2000
The oxidation of phospholipidbound docosahexaenoic acid (DHA) has been shown to be one of the major factors that limit the motile life span of sperm in vitro. Sperm samples show high cell-to-cell variability in life span and, consequently, in susceptibility toward lipid peroxidation. Therefore, we postulated that there is also cell-to-cell variability in DHA concentration in human spermatozoa. In this study, the concentration of DHA in subsets of human spermatozoa isolated by a discontinuous Percoll density gradient was determined by gas chromatography. Four subsets of human spermatozoa were isolated using a discontinuous Percoll gradient: fraction 1 was enriched in immature germ cells and immature sperm, fractions 2 and 3 contained, mostly, immature sperm with cytoplasmic droplets, and fraction 4 contained, for the most part, morphologically normal sperm, as determined by histochemical analysis. The results indicated that there were significant differences in DHA content in sperm from all 4 fractions. DHA content in sperm from fraction 1 was 2.5-fold higher than that found in fraction 4. DHA content in mouse sperm obtained from the seminiferous tubules was 3-fold higher than that found in mouse sperm obtained from the epididymis, consistent with the findings observed in ejaculated human sperm. The results of this study indicate (i) there is cell-to-cell variability in the concentration of DHA in human sperm and (ii) that there is a net decrease in DHA content in sperm during the process of sperm maturation. Mol.
Sperm fatty acid composition in subfertile men
Prostaglandins, Leukotrienes and Essential Fatty Acids, 2006
The lipid composition of spermatozoa plays an important role for successful fertilization. Patients and methods: In the present study, we analyzed the fatty acid (FA) composition of spermatozoa of normozoospermic, asthenozoospermic, oligozoospermic and oligoasthenozoospermic men. Results: Spermatozoa from asthenozoospermic (Po0.01), oligozoospermic (Po0.05) and oligoasthenozoospermic men (Po0.05) had lower levels of docosahexaenoic acid (22:6w3, DHA) than those from normozoospermic men. In oligozoospermic and asthenozoospermic men, spermatozoa 18:0 content was higher than that of normozoospermics (Po0.01 and Po0.001, respectively). 18:1w9 was higher in oligoasthenozoospermic and oligozoospermic samples when compared with normozoospermic samples (Po0.05 for both). While from the point of view of total w6 FAs there was no significant difference among the groups, the w6/w3 ratio was significantly higher in asthenozoospermic samples than in normozoospermic samples (Po0.05). Monounsaturated fatty acids (MFA) were higher in oligozoospermic samples (Po0.05) than in normozoospermic samples, polyunsaturated fatty acids (PUFA) were lower in asthenozoospermic (Po0.01), oligoasthenozoospermic (Po0.05) and oligozoospermic samples (Po0.05) than in normozoospermic samples.
Pattern of neutral and phospholipids in the semen of normospermic, oligospermic and azoospermic men
Reproduction, 1987
Total lipid concentration was elevated in the seminal plasma of oligo-and azoospermic men. The total cholesterol content was comparatively more in the seminal plasma of azoospermic men than in that of normo-and oligospermic men. In general, infertility was associated with increased seminal concentrations for most of the neutral lipid classes. However, total phospholipids and most of the phospholipid classes were diminished in the seminal plasma of oligoand azoospermic men and in the spermatozoa of oligospermic men. We suggest that there is a positive correlation between seminal phospholipids and fertility and a negative correlation between seminal neutral lipids and fertility.
2001
BACKGROUND: Reactive oxygen species (ROS)-induced damage of membrane phospholipids and DNA in human spermatozoa has been implicated in the pathogenesis of male infertility. In this study, variations in ROS production, DNA structure (as measured by the sperm chromatin structure assay) and lipid composition, were studied in human spermatozoa at different stages of maturation. METHODS: Sperm subsets were isolated by discontinuous density gradient centrifugation of semen samples obtained from healthy donors and from infertility patients. RESULTS: DNA damage and ROS production were highest in immature spermatozoa with cytoplasmic retention and abnormal head morphology, and lowest in mature spermatozoa. Docosahexaenoic acid and sterol content were highest in immature germ cells and immature spermatozoa, and lowest in mature spermatozoa. The relative proportion of ROS-producing immature spermatozoa in the sample was directly correlated with DNA damage in mature spermatozoa, and inversely correlated with the recovery of motile spermatozoa. There was no correlation between DNA damage and sperm morphology in mature spermatozoa. CONCLUSIONS: The high levels of ROS production and DNA damage observed in immature spermatozoa may be indicative of derangements in the regulation of spermiogenesis. DNA damage in mature spermatozoa may be the result of oxidative damage by ROS-producing immature spermatozoa during sperm migration from the seminiferous tubules to the epididymis.
Biology of Reproduction, 2015
In spermatozoa isolated from rat epididymis, lipids are differentially modified after in vitro induction of capacitation (Cap) and the acrosomal reaction (AR). This study uses Laurdan fluorescence generalized polarization values (GPv) to evaluate the effect of lipid changes occurring after isolation and functional activation on sperm membrane biophysical properties. In gametes isolated in the presence of a divalent cation chelator, no lipid changes occurred and the GPv were the lowest recorded, indicating maximal membrane lipid mobility. In sperm isolated as rapidly and gently as possible in the absence of chelator, part of the sphingomyelins (SM) were converted into ceramides (Cer), giving rise to higher GPv. In samples incubated as controls for Cap and AR, unchanged cholesterol and reduced glycerophospholipid levels were accompanied by the accumulation of free fatty acids (FFA), leading to even higher GPv. After completion of Cap, the GPv returned to lower levels as a result of the spermatozoa losing part of their cholesterol and FFA. Cap samples became relatively enriched in polyunsaturated fatty acids-containing plasmalogens because hydrolysis affected phosphatidyl rather than plasmenyl glycerophospholipid subclasses. The highest Cer:SM ratio and the highest GPv were found after completion of AR induced by A23187. The degree of SM ! Cer conversion among the samples, including controls, correlated with the extent of AR. FFA and Cer augmented GPv when added to liposomes prepared from the membrane lipid of intact sperm. Our results underscore the importance of hydrolytic changes that affect sperm lipids, especially the decisive lipid SM and Cer pair, not only after inducing sperm functional changes such as Cap and AR, but also under control conditions.
Molecular Reproduction and Development, 1995
Intact human sperm incorporated radiolabelled fatty acids into membrane phospholipids when incubated in medium containing bovine serum albumin as a fatty acid carrier. The polyunsturated fatty acids were preferentially incorporated into the plasmalogen fraction of phospholipid. Uptake was linear with time over 2 hr; at this time sufficient label was available to determine the loss of fatty acids under conditions of spontaneous lipid peroxidation. Loss of the various phospholipid types, the loss of the various fatty acids from these phospholipids, and the overall loss of fatty acids were all first order. The loss of saturated fatty acids was slow with first order rate constant k, = 0.003 hr-'; for the polyunsaturated fatty acids, arachidonic and docosahexaenoic acids, k, = 0.145 and 0.162 hr-', respectively. The rate of loss of fatty acids from the various phospholipid types was dependent on the type, with loss from phosphatidylethanolamine being the most rapid. Among the phospholipid types, phosphatidylethanolamine was lost at the greatest rate. Analysis of fatty acid loss through oxidation products was determined for radiolabelled arachidonic acid. Under conditions of spontaneous lipid peroxidation at 37°C under air in the absence of albumin, free arachidonic acid was found in the medium, along with minor amounts of hydroxylated derivative. All the hydroperoxy fatty acid remained in the cells. In the presence of albumin, all the hydroperoxy fatty acid was found in the supernatant bound to albumin; none could be detected in the cells. Albumin is known as a very potent inhibitor of lipid peroxidation in sperm; its action may be explained, based on these results, as binding the damaging hydroperoxy fatty acids. These results also indicate that a phospholipase A, may act in peroxidative defense by excising a hydroperoxy acyl group from phospholipid and providing the hydroperoxy fatty acid product as substrate to glutathione peroxidase. This formulation targets hydroperoxy fatty acid as a key intermediate in peroxidative degradation. o 1995 Wiley-Liss, Inc.
Human sperm lipid content is modified after migration into human cervical mucus
Molecular Human Reproduction, 2004
The effect of the female genital tract on sperm is not well known. To investigate the effect of cervical mucus on the lipid content of human sperm, we co-incubated sperm and mucus samples in vitro such that the sperm were able to swim in and out of the mucus samples. High performance liquid chromatography and UV detection were used to measure the lipid contents of the sperm and cervical mucus before and after migration. The concentrations of cholesterol, vitamin E, sphingomyelin, diacyls and plasmalogens in sperm were all~45% lower after migration in cervical mucus and the cervical mucus was found to be enriched in some of these lipid species after the sperm migration. These results suggest that the cervical mucus selects a subpopulation of sperm with a lower lipid content. However, a concomitant ef¯ux of various lipid classes from the sperm to the cervical mucus cannot be ruled out.