Dietary cholesterol-induced post-testicular infertility

Machine learning approach to assess the association between anthropometric, metabolic, and nutritional status and semen parameters

Many lifestyle factors, such as nutritional imbalance leading to obesity, metabolic disorders, and nutritional deficiency, have been identified as potential risk factors for male infertility. The aim of this study was to evaluate the relationship between semen parameters and anthropometric, metabolic and nutritional parameters. Relationship was first assessed individually, then after the application of a previously constructed and validated machine learning score that allows their combination. Anthropometric, metabolic, antioxidant, micronutrient, and sperm parameters from 75 men suffering from idiopathic infertility from four infertility centers in France (Jean-Verdier ART Center Hospital, Bondy; North Hospital ART Center, Saint-Étienne; Navarre Polyclinic ART Center, Pau; and Cochin Hospital ART Center, Paris) between September 2009 and December 2013 were collected. After assessing standard correlation analysis, a previously built machine learning model, providing a score ranging from 0 (the poorest) to 1 (the most favorable), was calculated for each man in the study cohort. This machine learning model, which separates infertile/fertile men with unexplained infertility on the basis of their bioclinical signature, provides a more holistic evaluation of the influence of the considered markers (anthropometric, metabolic, and oxidative status). We observed a significant correlation of some anthropometric, metabolic, and nutritional disorders with some sperm characteristics. Moreover, an unfavorable machine learning score was associated with a high level of sperm DNA fragmentation. Favorable anthropometric, metabolic, and oxidative patterns, which may reflect an appropriate lifestyle, appear to positively impact overall health, in particular reproductive function. This study, consistent with previous publications, suggests that beyond semen quality parameters, in an essential assessment of male fertility, other key factors should be taken into account. In this regard, the application of emerging artificial intelligence techniques may provide a unique opportunity to integrate all these parameters and deliver personalized care.

High cholesterol diet-induced testicular dysfunction in rats

PURPOSE

Hypercholesterolemia due to a high-cholesterol diet is linked to numerous diseases and may lead to male infertility. However, the underlying mechanism remains unknown. The maintenance of male fertility requires intact testicular structures (including seminiferous tubules and mesenchyme) and functioning cells (Leydig cells, Sertoli cells and germ cells, etc.), production of appropriate concentrations of sex hormones, and cooperation among testicular cells. Thus, we considered whether male fertility declined as the structure and function of testicular cells were altered in rats on a high-cholesterol diet.

METHODS

Male Sprague Dawley rats were fed either a standard or a high-cholesterol diet for 16 weeks. Serum sex hormones, lipid components, semen quality, and fertility rate were assayed in the rats. The 3β-hydroxysteroid dehydrogenase (3β-HSD), Wilms tumor 1 (WT-1), and deleted in azoospermia-like (DAZL) were regarded as specific markers of Leydig, Sertoli, and germ cells in rats. In addition, the ultrastructure of the testis and expression levels of particular marker molecules of testicular cells were further investigated.

RESULTS

Compared to rats fed on a regular diet, the serum testosterone levels and sperm progressive motility decreased in rats fed high cholesterol. Moreover, we observed a deformed nucleus, dilated smooth endoplasmic reticulum, and swollen mitochondria of Leydig cells and a schizolytic nucleus of Sertoli cells in rats on a high-cholesterol diet. The 3β-HSD, WT-1, and DAZL protein expression levels were significantly reduced in rats on a high-cholesterol diet.

CONCLUSIONS

Our results showed that a high-cholesterol diet adversely affected testosterone production and sperm progressive motility, possibly due to Leydig, Sertoli, and germ cell abnormalities.

Serum lipid profile levels and semen quality: new insights and clinical perspectives for male infertility and men's health

PURPOSE

Several clinical scenarios regulate the final ejaculated semen, which is pivotal to reproductive success. Sperm motility and plasma membrane fusogenic activity primarily rely on the peculiar sperm lipid composition, influenced by the patient's metabolism, genetics, nutritional, environmental status, and concomitant clinical entities such as varicocele. This study aimed to determine the relationship between serum lipid profile and testicular function (semen quality and testosterone levels).

METHODS

This retrospective study uses medical charts of 278 infertile men who attended andrological care between 2000 and 2019. Seminal analysis data, lipid profile, and total serum testosterone were collected. A multiple linear regression analysis was performed to evaluate the influence of the lipid parameters on the seminal variables. Statistical analyses were carried out with p ≤ 0.05 considered statistically significant.

RESULTS

Seminal creatine kinase activity (p = 0.024) is negatively related to HDL (p = 0.032) and triglycerides (p = 0.037), while total testosterone (p < 0.0001) and seminal volume (p = 0.046) appeared both to be negatively related to triglycerides (p = 0.030 and p = 0.033, respectively).

CONCLUSION

Medical advice commonly advocated to prevent endothelial dysfunction and cardiovascular disease and improve HDL-cholesterol and triglyceride levels in dyslipidemic patients should also be given to infertile men. Physicians should give patients a thorough assessment, including the blood lipid profile, hormonal status, and routine seminal examinations. We propose a more comprehensive men´s health check-up for the infertile male population, not limited to a simple evaluation of basic sperm parameters.

Extra-virgin olive oil ameliorates high-fat diet-induced seminal and testicular disorders by modulating the cholesterol pathway

BACKGROUND

Rabbits are sensitive to dietary cholesterol and rapidly develop hypercholesterolemia, leading to prominent subfertility. Sterol regulatory element-binding protein isoform 2 drives the intracellular cholesterol pathway in many tissues, including the testicles. Its abnormal regulation could be the mainly responsible for the failure of suppressing cholesterol synthesis in a cholesterol-enriched environment, ultimately leading to testicular and seminal alterations. However, extra-virgin olive oil consumption has beneficial properties that promote lowering of cholesterol levels, including the recovery of seminal parameters altered under a high-fat diet.

OBJECTIVES

Our goal was to investigate the effects of high-fat diet supplementation with extra-virgin olive oil at the molecular level on rabbit testes, by analyzing sterol regulatory element-binding protein isoform 2 protein and its corresponding downstream effectors.

MATERIALS AND METHODS

During 12 months, male rabbits were fed a control diet, high-fat diet, or 6-month high-fat diet followed by 6-month high-fat diet plus extra-virgin olive oil. Serum lipids, testosterone levels, bodyweight, and seminal parameters were tested. The mRNA and protein levels of sterol regulatory element-binding protein isoform 2, 3-hydroxy-3-methyl-glutaryl-coenzyme A reductase, and low-density lipoprotein receptor were determined by semi-quantitative polymerase chain reaction and Western blotting techniques. The expression pattern of sterol regulatory element-binding protein isoform 2 protein in the rabbit testicles was studied by indirect immunofluorescence. In addition, testicular cholesterol was detected and quantified by filipin staining and gas chromatography.

RESULTS

The data showed that the addition of extra-virgin olive oil to high-fat diet reduced testicular cholesterol levels and recovered the expression of sterol regulatory element-binding protein isoform 2, 3-hydroxy-3-methyl-glutaryl-coenzyme A reductase, and low-density lipoprotein receptor initially altered by the high-fat diet.

DISCUSSION AND CONCLUSIONS

The combination of high-fat diet with extra-virgin olive oil encourages testicular recovery by modifying the expression of the enzymes related to intracellular cholesterol management.

Comprehensive metabolomics profiling of seminal plasma in asthenozoospermia caused by different etiologies

BACKGROUND

Asthenozoospermia (AZS) is a disease characterized by decreased sperm motility induced by multiple etiologies, and the pathological mechanisms of various AZS are unclear. We simultaneously analyzed the metabolic profiling of four representative AZS to provide new insights into the etiologies of AZS.

METHOD

Seminal plasma samples were collected from healthy control (HC; n = 30) and four AZS induced by varicocele (VA, n = 30), obesity (OA, n = 22), reproductive system infections (RA; n = 17) and idiopathic (IA, n = 30), respectively, and were analyzed using gas chromatography-mass spectrometry. Disturbed metabolites and metabolic pathways were compared between AZS and HC, as well as IA and the other three AZS.

RESULTS

A total of 40 different metabolites were identified in the seminal plasma of AZS and HC, of which lactic acid, fructose, citric acid, glutamine and pyruvic acid metabolic abnormalities associated with all the AZS groups, while each AZS group had unique metabolic changes. RA was significantly separated from the other three AZS, and metabolites such as cholesterol, octadecanoic acid and serine mainly contributed to the separation.

CONCLUSION

The comprehensive metabolomic analysis and comparison of four various AZS provided evidence and clues for the mechanism mining, which will benefit future etiology, diagnosis and treatment of AZS.

MRI determined prostate volume and the incidence of prostate cancer on MRI-fusion biopsy: a systemic review of reported data for the last 20 years

PURPOSE

Magnetic resonance imaging (MRI) is a precise, systemic and advantageous imaging technique when compared to transrectal ultrasound (TRUS) which is very operator dependent. The negative correlation between prostate volume and the incidence of prostate cancer (PCa) obtained by TRUS biopsy has been well documented in the literature. The purpose of this systemic review is analyzing the reported MRI-fusion study results on prostate biopsies regarding any correlation between prostate volume and the incidence of PCa.

METHODS

After defining the inclusion and exclusion criteria an in-depth review were performed between 01.01.2000 and 02.08.2022 using the PubMed database and applying the "PRISMA" guidelines.

RESULTS

Twelve studies qualified, and all showed an inverse/negative relationship between prostate volume and incidence of PCa. Sample sizes ranged from 33 to 2767 patients in single and multi-institutional studies. All studies showed a statistically significant inverse relationship with a p value < 0.05. The graph summarizing all of studies and using Fisher's method revealed a highly significant combined p level of 0.00001. Additionally, not one single study was found showing the contrary (a positive correlation between prostate size and the incidence of PCa).

CONCLUSION

To our knowledge, this is the first systemic review of reported MRI-Fusion data on the incidence of PCa in correlation with prostate volume. This MRI review confirms previous TRUS-biopsy studies which demonstrated an inverse relationship between prostate volume and the incidence of PCa, and thus further supports the hypothesis that large prostates size may be protective against PCa when compared to smaller prostates.

L-Carnitine effect on induced hyperlipidemia on premature rats: fertility profile

This study was designed to investigate the effect of hypercholesterolemia on the reproductive performance of premature male rats and to evaluate the influence of L-Carnitine (CAR) in maintaining their fertility. Sixty rats were divided randomly into three groups. Control group (CG n=20 rats), cholesterol feeding group 1 (CFG1 n=20 rats) fed 1.5% cholesterol with diet for one month, and cholesterol feeding group 2 (CFG2 n=20 rats) fed 1.5% cholesterol with diet + CAR 150 mg/kg body weight (B.W.) given by water for one month. Results showed a significant increase in body weight of CFG1 compared with CG and CFG2. The lipid profile of CFG1 after one month of feeding cholesterol showed a significant increase in serum cholesterol and triglyceride compared with CG and with the group that watered by CAR and CFG2. Results of sperms parameters in CGF2 showed a significant increase in sperms count with sperms live percentage and a significant decrease in sperms abnormalities percentage compared with CGF1 and CG. The hormonal profile showed a significant decrease in serum testosterone levels in rats from CFG1 compared with CFG2 and CG. In conclusion, CAR is a powerful antioxidant that can maintain the parameters of sperms of hypercholesterolemic premature rats, which may enhance the fertilizing ability of subfertile rats that may occur due to hyperlipidemia.

Comparison between the Antioxidant and Antidiabetic Activity of Fenugreek and Buckthorn in Streptozotocin-Induced Diabetic Male Rats

This study is aimed at comparing the antidiabetic and antioxidant potential of fenugreek and buckthorn which are commonly used in modulating diabetes in the Middle East. In this study, the antioxidant and antidiabetic activity of the aqueous extracts of the leaf and seed of fenugreek and buckthorn was tested in streptozotocin-induced diabetic male rats fed with a fat-rich diet for 8 weeks. Thirty-six male albino rats were divided into 6 groups (n = 6); the 1st group was the negative control. Diabetes was induced in the other 30 rats using streptozotocin, which were then divided into 5 groups; the 2nd was the untreated positive diabetic group, the 3rd was treated with fenugreek leaf aqueous extract, the 4th was treated with the fenugreek seed aqueous extract, the 5th was treated with buckthorn leaf aqueous extract, and the 6th was treated with buckthorn seed aqueous extract. The positive control group showed an increase in blood sugar, glycated hemoglobin, liver function enzymes, lactate dehydrogenase, kidney indices, total cholesterol, triglycerides, low- and very-low-density lipoprotein, immunoglobulins, and lipid peroxidation and a decrease in high-density lipoprotein, albumin, and antioxidant activity. The histology of the liver and testes showed severe histopathological alterations. Rats of groups 4-6 that were treated with the aqueous extract of the leaf and seed extract of fenugreek and buckthorn showed improvement of all biochemical and histopathological parameters. The seed extract of fenugreek and buckthorn showed more antioxidant activity than their leaves.

Rescue effect of sodium acetate in diabetes mellitus-associated testicular dysfunction is accompanied by PCSK9 modulation

Diabetes mellitus (DM) is a global health burden, affecting about 463 million of the adult population worldwide. Approximately 94% of diabetic male individuals develop varying degrees of testicular disorders (TDs), which usually result in hypogonadism, hypotestosteronemia and defective spermatogenesis and steroidogenesis. Short chain fatty acids (SCFAs) have shown potential benefits in metabolic health. However, its effect on TD associated with DM is not clear. Howbeit, the present study investigated the hypothesis that SCFAs, acetate would ameliorate TD accompanying DM, possibly by suppressing proprotein convertase subtilisin/kexin type 9 (PCSK9). Male Wistar rats (210-240 g) were allotted into groups (n = 6/group): control (vehicle; po), DM with/without 200 mg/kg (po) of sodium acetate (SAc). Diabetes was induced by streptozotocin 65 mg/kg (iv) after a dose of nicotinamide (110 mg/kg). Semen/biochemical and histological analyses were performed with appropriate methods. In addition to hyperglycemia, hyperinsulinemia and reduced insulin sensitivity, DM led to increased serum and testicular triglyceride or total cholesterol/high-density lipoprotein cholesterol ratio, low-density lipoprotein cholesterol, malondialdehyde, TNF-α, IL-6 and PCSK9 as well as reduced high-density lipoprotein cholesterol and glutathione. Moreover, DM caused TD which is characterized by altered sperm parameters, disrupted tissue architecture, atrophied seminiferous tubules, deleterious spermatogonia, disappearance of lumen and cellular degeneration as well as decreased luteinizing hormone and testosterone. However, the administration of SAc attenuated these alterations. The study demonstrates that DM-induced TD is accompanied by elevated PCSK9. The results however suggest that SAc rescues testicular disorder/dysfunction associated with DM by suppression of PCSK9 and improvement of insulin sensitivity.

High fat diet impairs spermatogenesis by regulating glucose and lipid metabolism in Sertoli cells

AIMS

Sertoli cells (SCs) play an important role in the process of spermatogenesis. SCs provide energy for germ cells (GCs) and themselves through glycolysis and fatty acid oxidation (FAO) respectively. High fat diet (HFD) impairs spermatogenesis by damaging function of SCs, however whether HFD disrupts energy metabolism in SCs remains unclear.

MAIN METHODS

To explore this hypothesis, we built male Wistar rat model fed on HFD and cultured rats' primary SCs with palmitic acid (PA). Rats' fertility and sperm quality were evaluated in vivo. Glycolysis, lactate production and mitochondrial respiration were assessed by using extracellular flux analyzer, and the expression of enzymes involved in glucose and FAO was analyzed by Real-Time PCR or Western Blotting.

KEY FINDINGS

The showed that the sperm concentration and pups per litter significantly decreased in rats fed on HFD compared to those rats fed on normal diet. There was an elevation of lactate levels in testicular tissue of rats fed on HFD and primary SCs exposed to PA. In vitro, PA increased glycolytic flux, and lactate production, and the levels of carnitine palmitoyltransferase I (CPT1) and long chain acyl-CoA dehydrogenase (LCAD) which were two key enzymes for fatty acid β oxidation. Further analysis showed that mitochondrial respiration was impaired by PA, followed by the decrease in ATP turnover, maximal respiration and the increase in proton leak.

SIGNIFICANCE

Taken together, the elevated lactate level, lipid metabolism disorder and mitochondrial dysfunction caused by HFD lead to SCs dysfunction, which ultimately leads to decreased sperm quality.

Trihoney ameliorates hypercholesterolemia-induced epididymal histopathological changes in male rabbits

Hypercholesterolemia has been linked to weight change and histopathological alteration of male reproductive organs. The epididymis was suggested to be an early target of lipid-related infertility and can be dramatically affected by excess intake of a high cholesterol diet. On the other hand, the interest has been increased towards the use of honey as a prophylactic and therapeutic agent for various diseases. Therefore, the purpose of this study is to investigate the effects of Trihoney (a mixture of Trigona, Mellifera and Tualang) on epididymal weight change and histopathological alterations in hypercholesterolemic male rabbits and compare its effects with atorvastatin. Forty-eight mature male New Zealand white rabbits were divided into 6 groups. Two groups received standard rabbit pellet with 0 and 0.6 g/kg/day of Trihoney respectively while the other four groups received 1% cholesterol diet with 0, 0.3, 0.6 g/kg/day of Trihoney, and 2 mg/kg/day of atorvastatin. After 12 weeks, the rabbits were sacrificed and the epididymides were harvested for evaluation of weight and histopathological changes. Administration of 1% cholesterol diet either alone or in combination with atorvastatin caused a significant reduction in the epididymal weight and epididymal atrophy. Supplementation of Trihoney particularly at the dose of 0.6 g/kg/day improved epididymal weight, regained the normal architecture of the epididymal histology and increased the number of mature sperm inside the tubules of the epididymis. Based on these results, Trihoney exhibited its potential health benefit as a protective agent against epididymal weight reduction and histopathological alterations in hypercholesterolemic rabbits.

Dietary Cholesterol and Lipid Overload: Impact on Male Fertility

Lipid metabolic disorders due to poor eating habits are on the rise in both developed and developing countries, with a negative impact of the "Western diet" on sperm count and quality. Dietary lipid imbalance can involve cholesterol, fatty acids, or both, under different pathophysiological conditions grouped under the term dyslipidemia. The general feature of dyslipidemia is the development of systemic oxidative stress, a well-known deleterious factor for the quality of male gametes and associated with infertility. Sperm are particularly rich in polyunsaturated fatty acids (PUFA), an important characteristic associated with normal sperm physiology and reproductive outcomes, but also targets of choice for oxidative thrust. This review focuses on the effects of dietary cholesterol or different fatty acid overload on sperm composition and function in both animals and humans. The links between oxidative stress induced by dyslipidemia and sperm dysfunction are then discussed, including possible preventive or therapeutic strategies to preserve gamete quality, longevity when stored in cryobanking, and male fertility.

Liver X Receptors and Male (In)fertility

Liver X receptors (LXRs) are ligand-dependent transcription factors acting as ‘cholesterol sensors’ to regulate lipid homeostasis in cells. The two isoforms, LXRα (NR1H3) and LXRβ (NR1H2), are differentially expressed, with the former expressed predominantly in metabolically active tissues and the latter more ubiquitously. Both are activated by oxidised cholesterol metabolites, endogenously produced oxysterols. LXRs have important roles in lipid metabolism and inflammation, plus a number of newly emerging roles. They are implicated in regulating lipid balance in normal male reproductive function and may provide a link between male infertility and lipid disorders and/or obesity. Studies from Lxr knockout mouse models provide compelling evidence to support this. More recently published data suggest distinct and overlapping roles of the LXR isoforms in the testis and recent evidence of a role for LXRs in human male fertility. This review summarises the current literature and explores the likely link between LXR, lipid metabolism and male fertility as part of a special issue on Liver X receptors in International Journal of Molecular Sciences.

Impairment of sperm maturation and capacitation due to diet-dependent cholesterol overload

BACKGROUND

Lipid metabolic disorders (dyslipidemia) are constantly increasing in occidental societies and lead to the development of pathologies such as obesity, diabetes, and metabolic syndrome. It has been demonstrated that dyslipidemia can alter the reproductive function. Animal models have recently been used to show that the offspring of dyslipidemic males could also develop such pathologies and that the transgenerational transmission involved post-testicular sperm maturation. These data targeted the essential role of male gamete epididymal maturation and its importance for the health of the offspring.

OBJECTIVES

This publication summarizes in the first place experimental data obtained using a mouse model of dyslipidemia-induced post-testicular infertility, knockout mice for the two isoforms of the 'Liver X Receptors' (Lxrα;β^-/- ), the major regulators of cholesterol homeostasis. The impact of a high cholesterol diet (HCD) on the protein YWHAZ (14-3-3 ζ or tyrosine 3-monooxygenase/tryptophan 5-monooxygenase activation protein Zeta) was also investigated in our model.

MATERIALS AND METHODS

In our mouse model, when young fertile Lxrα;β^-/- males aged three months were fed four weeks with a HCD, they developed an epididymal phenotype leading to infertility. The level of sperm YWHAZ was evaluated by Western blot and its tyrosine phosphorylation state by immunoprecipitation followed by Western blot.

RESULTS

Our data revealed that sperm lipid composition and structure were altered, leading to defects of the capacitation-associated signaling pathway. They also showed that both the level and the tyrosine phosphorylation state of YWHAZ were affected by the HCD in sperm cells from Lxrα;β^-/- males.

DISCUSSION AND CONCLUSION

YWHAZ could be a new important regulator of capacitation-associated tyrosine phosphorylation and a marker of dyslipidemia-induced infertility.

Morbid obesity-related changes in the expression of lipid receptors, transporters, and HSL in human sperm

OBJECTIVE

To study the location and expression of receptors (SR-BI/CLA-1, SR-BII, and LDLr) and transporter (ABCA1) involved in uptake and efflux of cholesterol in human spermatozoa and assess whether obesity alters its location/expression and whether this could be related to infertility.

DESIGN

Observational study.

SETTING

None PATIENT(S): Ten controls and 20 obese patients.

INTERVENTION(S)

Anthropometric parameters. Serum and semen samples were collected.

MAIN OUTCOME MEASURE(S)

Spermatozoon concentration, immunolocalization, and protein expression in semen.

RESULTS

Spermatozoon concentration and motility was decreased in morbidly obese patients. SR-BI/CLA-1, SR-BII, LDLr, and ABCA1 are located in the spermatozoon cell membrane and the localization does not change between obese patients and controls. Control spermatozoa showed high SR-BI expression, and less expression for the rest of the receptors analyzed, indicating that SR-BI/CLA-1 is relevant in human spermatozoon cholesterol uptake/efflux. On the contrary, spermatozoa of obese patients showed less SR-BI/CLA-1 expression than controls, and more intense positive staining for SR-BII, LDLr, and ABCA1. Finally, human sperm expresses the 130- and 82-kDa hormone-sensitive lipase (HSL) isoforms. The 130-kDa isoform is expressed in the control sperm, and the expression disappears in the obese patients.

CONCLUSION(S)

The presence of lipid receptors/transporters and HSL in human spermatozoa suggests their role in the process of maturation/capacitation. The changes in the expression of lipid receptors/transporters and the lack of the 130-kDa HSL isoform in obese patients prevent the hydrolysis of cholesterol esters internalized by these receptors, and favor their accumulation in the cytoplasm of the spermatozoa that could contribute to lipotoxicity and infertility.

Dyslipidemia alters sperm maturation and capacitation in LXR-null mice

Lipid metabolism disorders (dyslipidemia) are causes of male infertility, but little is known about their impact on male gametes when considering post-testicular maturation events, given that studies concentrate most often on endocrine dysfunctions and testicular consequences. In this study, three-month-old wild-type (wt) and Liver-X-Receptors knock out (Lxrα;β−/−) males were fed four weeks with a control or a lipid-enriched diet containing 1.25% cholesterol (high cholesterol diet (HCD)). The HCD triggered a dyslipidemia leading to sperm post-testicular alterations and infertility. Sperm lipids were analyzed by LC–MS and those fromLxrα;β−/−males fed the HCD showed higher chol/PL and PC/PE ratios compared towt-HCD (P < 0.05) and lower oxysterol contents compared to wt (P < 0.05) orLxrα;β−/−(P < 0.05). These modifications impaired membrane-associated events triggering the tyrosine phosphorylation normally occurring during the capacitation process, as shown by phosphotyrosine Western blots. Using flow cytometry, we showed that a smaller subpopulation of spermatozoa fromLxrα;β−/−-HCD males could raise their membrane fluidity during capacitation (P < 0.05 vswtorwt-HCD) as well as their intracellular calcium concentration (P < 0.05 vsLxrα;β−/−andP < 0.001 vswt). The accumulation of the major sperm calcium efflux pump (PMCA4) was decreased inLxrα;β−/−males fed the HCD (P < 0.05 vsLxrα;β−/−andP < 0.001 vswt). This study is the first showing an impact of dyslipidemia on post-testicular sperm maturation with consequences on the capacitation signaling cascade. It may lead to the identification of fertility prognostic markers in this pathophysiological situation, which could help clinicians to better understand male infertilities which are thus far classified as idiopathic.

Manchette-acrosome disorders during spermiogenesis and low efficiency of seminiferous tubules in hypercholesterolemic rabbit model

Hypercholesterolemia is a marker for several adult chronic diseases. Recently we demonstrated that sub/infertility is also associated to Hypercholesterolemia in rabbits. Seminal alterations included: abnormal sperm morphology, decreased sperm number and declined percentage of motile sperm, among others. In this work, our objective was to evaluate the effects of hypercholesterolemia on testicular efficiency and spermiogenesis, as the latter are directly related to sperm number and morphology respectively. Tubular efficiency was determined by comparing total number of spermatogenic cells with each cell type within the proliferation/differentiation compartments. We found lower testicular efficiency related to both a decrease in spermatogonial cells and an increase in germ cell apoptosis in hypercholesterolemic rabbits. On the other hand, spermiogenesis-the last step of spermatogenesis involved in sperm shaping-was detaily analyzed, particularly the acrosome-nucleus-manchette complex. The manchette is a microtubular-based temporary structure responsible in sperm cell elongation. We analyzed the contribution of actin filaments and raft microdomains in the arrangement of the manchette. Under fluorescence microscopy, spermatocyte to sperm cell development was followed in cells isolated from V to VIII tubular stages. In cells from hypercholesterolemic rabbits, abnormal development of acrosome, nucleus and inaccurate tail implantation were associated with actin-alpha-tubulin-GM1 sphingolipid altered distribution. Morphological alterations were also observed at electron microscopy. We demonstrated for the first time that GM1-enriched microdomains together with actin filaments and microtubules are involved in allowing the correct anchoring of the manchette complex. In conclusion, cholesterol enriched diets promote male fertility alterations by affecting critical steps in sperm development: spermatogenesis and spermiogenesis. It was also demonstrated that hypercholesterolemic rabbit model is a useful tool to study serum cholesterol increment linked to sub/infertility.

Posttesticular sperm maturation, infertility, and hypercholesterolemia

Cholesterol is a key molecule in the mammalian physiology of especial particular importance for the reproductive system as it is the common precursor for steroid hormone synthesis. Cholesterol is also a recognized modulator of sperm functions, not only at the level of gametogenesis. Cholesterol homeostasis regulation is crucial for posttesticular sperm maturation, and imbalanced cholesterol levels may particularly affect these posttesticular events. Metabolic lipid disorders (dyslipidemia) affect male fertility but are most of the time studied from the angle of endocrine/testicular consequences. This review will focus on the deleterious effects of a particular dyslipidemia, i.e., hypercholesterolemia, on posttesticular maturation of mammalian spermatozoa.

The Efficiency of Barley (Hordeum vulgare) Bran in Ameliorating Blood and Treating Fatty Heart and Liver of Male Rats

The current study focused on testing the hypolipidemic activity of two doses of barley bran on hypercholesterolemic male rats. Twenty-four male albino rats weighing 180–200 gm were divided into four groups. The first group (G1) was the negative control, the second group (G2) was the positive control group fed 2% cholesterol in the diet, and rats of the third and the fourth groups were fed 2% cholesterol and were cosupplemented with 5% and 10% barley bran, respectively, for 8 weeks. The hypercholesterolemic rats of (G2) showed an increase in lipid profile, liver enzymes, lactate dehydrogenase, creatine kinase-MB, and lipid peroxide and a decrease in antioxidant enzymes, whereas kidney function, fasting blood sugar, glycated hemoglobin total protein, and total bilirubin were not significantly affected compared with the negative control group in G1. Moreover, histology of heart, liver, and kidney of G2 rats showed histopathological changes compared with the negative control. Administration of the two doses of barley bran in G3 and G4 to the hypercholesterolemic rats ameliorated the level of lipids, liver enzymes, lactate dehydrogenase, and creatine kinase-MB. In addition, the histology of heart, liver, and kidney tissues nearly restored the normal state as in G1.

A hybrid computational method for the discovery of novel reproduction-related genes

Uncovering the molecular mechanisms underlying reproduction is of great importance to infertility treatment and to the generation of healthy offspring. In this study, we discovered novel reproduction-related genes with a hybrid computational method, integrating three different types of method, which offered new clues for further reproduction research. This method was first executed on a weighted graph, constructed based on known protein-protein interactions, to search the shortest paths connecting any two known reproduction-related genes. Genes occurring in these paths were deemed to have a special relationship with reproduction. These newly discovered genes were filtered with a randomization test. Then, the remaining genes were further selected according to their associations with known reproduction-related genes measured by protein-protein interaction score and alignment score obtained by BLAST. The in-depth analysis of the high confidence novel reproduction genes revealed hidden mechanisms of reproduction and provided guidelines for further experimental validations.

Metabolic syndrome-associated sperm alterations in an experimental rabbit model: relation with metabolic profile, testis and epididymis gene expression and effect of tamoxifen treatment

The influence of metabolic syndrome (MetS) on sperm quality and function is debated. Using a well-established high fat diet (HFD) rabbit model resembling human MetS, including development of hypogonadism, we demonstrate that HFD decreased sperm motility, morphology and acrosome reaction in response to progesterone and increased sperm cholesterol content. All the above parameters were associated with most MetS features, its severity and plasma testosterone (T) at univariate analysis. After T adjustment, sperm morphology and motility retained a significant association, respectively, with mean arterial pressure and circulating cholesterol levels. MetS modified the expression of inflammatory and tissue remodelling genes in the testis and of aquaporins in the epididymis. In a multivariate analysis, sperm morphology resulted associated with testis expression of fibronectin and collagen type 1 genes, whereas motility with epididymis aquaporin 1 gene. Administration of tamoxifen, used in the treatment of idiopathic male infertility, to HFD rabbits partially restored motility, but further decreased morphology and increased spontaneous acrosome reaction, without restoring responsiveness to progesterone. Overall our results indicate that development of MetS produces detrimental effects on sperm quality and functionality by inducing metabolic disorders leading to alterations in testis and epididymis functions and evidence a role of hypertension as a new determinant of abnormal sperm morphology, in line with a previous human study from our group.

Efficiency of barley bran and oat bran in ameliorating blood lipid profile and the adverse histological changes in hypercholesterolemic male rats

The efficiency of oat bran and barley bran in lowering the induced hyperlipidemia and hypercholesterolemia in blood of male Albino rats (Rattus rattus) was studied. Twenty rats were divided into four groups each consisted of five rats and fed the specified test diets for eight weeks. The first group (G1) is the negative group which was fed basal diet, the second group (G2) was fed 1.0% cholesterol, was the third group (G3) fed 1.0% cholesterol and 10% oats bran, and the fourth group (G4) was fed 1.0% cholesterol and 10% barley bran. Feeding rats on 1% cholesterol significantly increased serum total cholesterol, low density lipoprotein, and very low density lipoprotein and triglyceride and decreased serum high density lipoprotein. Furthermore, enzyme activity of alanine aminotransferase, aspartate aminotransferase, and alkaline phosphatase was increased, and lipid peroxide was increased, whereas catalase and glutathione-S-transferase were decreased. Kidney functions parameters in the cholesterol supplemented group were elevated compared with the negative control. In addition, histological alteration in kidney, liver, heart, and testes was observed, compared with the negative control. Hypercholesterolemic rats supplemented with oat bran and barley bran showed significant decrease in lipid parameters, significant increase in high density lipoprotein-cholesterol, improved antioxidant enzyme, and improved histopathology of kidney, liver, heart, and testes. In conclusion, both oat bran and barley bran had protective effects against induced hyperlipidemia and improved histological alterations. Oat bran appeared more efficient than barley bran in lowering the lipid profile levels in hypercholesterolemic rats.

Semen quality and sperm function loss by hypercholesterolemic diet was recovered by addition of olive oil to diet in rabbit

Fat increment (0.05% cholesterol, chol) in standard diet promoted a significant increase in serum and sperm membrane chol, which ultimately altered membrane-coupled sperm specific functions: osmotic resistance, acrosomal reaction, and sperm capacitation in White New Zealand rabbits. These changes were also associated with a reduction in motility percentage and appearance of abnormal sperm morphology. The present study was carried out to evaluate the effect of dietary olive oil (OO, 7% v/w) administration to several male hypercholesterolemic rabbits (hypercholesterolemic rabbits, HCR) with altered fertility parameters. These HCR males were achieved by feeding normal rabbits with a high-fat diet (0.05% chol). HCR were associated with a modest non-significant increase in body weight (standard diet, 4.08±0.17 Kg, versus high-fat diet, 4.37±0.24 Kg). Hypercholesterolemic rabbits presented a marked decrease in semen volume, sperm cell count, and percentage of sperm motility, associated with a significant increase in sperm cell abnormalities. Moreover, sperm capacitation measured by the characteristic phosphorylated protein pattern in and induced acrosomal reaction were also altered suggesting sperm dysfunction. However, the administration of OO (for 16 weeks) to rabbits that were fed with 50% of the high-fat diet normalized serum chol. Curiously, OO supply succeeded to attenuate the seminal and sperm alterations observed in HCR group. Administration of OO alone did not cause any significant changes in above mentioned parameters. These data suggest that OO administration to HCR male rabbits recovers the loss of semen quality and sperm functionality.

Sterols in spermatogenesis and sperm maturation

Mammalian spermatogenesis is a complex developmental program in which a diploid progenitor germ cell transforms into highly specialized spermatozoa. One intriguing aspect of sperm production is the dynamic change in membrane lipid composition that occurs throughout spermatogenesis. Cholesterol content, as well as its intermediates, differs vastly between the male reproductive system and nongonadal tissues. Accumulation of cholesterol precursors such as testis meiosis-activating sterol and desmosterol is observed in testes and spermatozoa from several mammalian species. Moreover, cholesterogenic genes, especially meiosis-activating sterol-producing enzyme cytochrome P450 lanosterol 14α-demethylase, display stage-specific expression patterns during spermatogenesis. Discrepancies in gene expression patterns suggest a complex temporal and cell-type specific regulation of sterol compounds during spermatogenesis, which also involves dynamic interactions between germ and Sertoli cells. The functional importance of sterol compounds in sperm production is further supported by the modulation of sterol composition in spermatozoal membranes during epididymal transit and in the female reproductive tract, which is a prerequisite for successful fertilization. However, the exact role of sterols in male reproduction is unknown. This review discusses sterol dynamics in sperm maturation and describes recent methodological advances that will help to illuminate the complexity of sperm formation and function.