Monika Fraczek

Membrane stability and mitochondrial activity of human-ejaculated spermatozoa during in vitro experimental infection with Escherichia coli, Staphylococcus haemolyticus and Bacteroides ureolyticus

The aim of the study was to examine an in vitro effect of the three bacterial strains (Escherichia coli, Staphylococcus haemolyticus and Bacteroides ureolyticus) on ejaculated spermatozoa with reference to sperm membrane integrity and mitochondrial activity. The study was carried out on swim‐up‐separated spermatozoa from 12 normozoospermic volunteers. Sperm plasma membrane stability was evaluated by the LIVE/DEAD Sperm Viability Kit and by the merocyanine 540 test. Mitochondrial activity was evaluated using the JC‐1 test as well as the NADH‐dependent NBT assay. The percentage of dead cells was significantly higher in spermatozoa treated with B. ureolyticus as compared to that of control spermatozoa (P < 0.01). All the bacterial strains applied affected sperm plasma membrane architecture measured by M540 test (P < 0.01). Moreover, the presence of E. coli or B. ureolyticus was connected with significant decrease in both the number of cells with high mitochondrial transmembrane potential (ΔΨm) and the cells with normal oxidoreductive function of mitochondria (P < 0.05 as compared to untreated cells). To conclude, the contact of bacteria with ejaculated spermatozoa can be a reason for severe injury of sperm membrane stability and mitochondrial activity with potential consequences for male fertility.

Cytokines in the male reproductive tract and their role in infertility disorders

Cell integration between the immune and reproductive systems is the basis for normal male reproductive physiology. Cytokines are a part of the autocrine/paracrine network operating in the male reproductive tract. At the same time, immunological reactions occurring via cytokines appear to be both beneficial and/or risk factors for male fertility. As the cytokines are produced by a whole spectrum of cells in all compartments of the male genital tract, they can also be involved in a variety of andrological disorders. The monitoring of cytokines and other immune factors in seminal plasma may offer a chance to better understand the mechanisms leading to sub-/infertility. In this review, we present insights into cytokine interplay in some of the pathological conditions associated with male reproduction.

Mechanisms of the harmful effects of bacterial semen infection on ejaculated human spermatozoa: potential inflammatory markers in semen.

The invasion of the male reproductive tract by microorganisms, and its subsequent consequences for sperm fertilizing potential, has been intensely discussed. The role of the bacteria that are responsible for the colonization and contamination of the male urogenital tract, rather than its infection, in diminished sperm parameters raises the most controversy. There are numerous premises suggesting that bacterial semen infection is associated with male infertility. However, the molecular mechanism by which the fertility is affected is complex and multifactorial, and still presents a puzzle. Some authors have suggested that direct interactions between bacteria and human spermatozoa facilitate sperm immobilization, affect sperm morphology, and thus weaken the ability of sperm to fertilize. On the other hand, the massive infiltration of activated leukocytes into the inflammatory site may be associated with impairment of sperm fertilizing potential, due to oxidative, apoptotic, and immune processes. This review presents current research trends and aims to summarize the present knowledge of semen inflammation and causative bacterial agents in the male urogenital tract, with its consequence on seminological parameters, and male fertility status.

Can apoptosis and necrosis coexist in ejaculated human spermatozoa during in vitro semen bacterial infection

PurposeTo evaluate whether ejaculated human spermatozoa undergo complete apoptosis or necrosis during experimental semen bacterial infection in vitro.MethodsApoptotic markers, including mitochondrial transmembrane potential (ΔΨm), phosphatidylserine (PS) externalization, and DNA fragmentation, have been detected simultaneously in ejaculated human sperm after their incubation with a known pathogenic (Escherichia coli), as well as with conditionally pathogenic bacterial strains (Staphylococcus haemolyticus, Bacteroides ureolyticus) and/or leukocytes. The ΔΨm and translocation of PS was evaluated using the JC-1 and Annexin V binding tests, respectively. A modified TUNEL assay with additional staining for sperm viability was used to detect the DNA fragmentation level.ResultsThe exposure of ejaculated spermatozoa to bacterial strains was associated with a simultaneous decrease in the percentage of sperm with normal ΔΨm and an increase in the proportion of Annexin V-positive sperm. Additionally, in the presence of S. haemolyticus, B. ureolyticus and/or leukocytes, a significant increase in the percentage of live TUNEL-positive (apoptotic) as well as dead TUNEL-positive (necrotic) sperm cells was also observed.ConclusionsThe cellular death observed in spermatozoa in the presence of inflammatory mediators may be due to both apoptosis and necrosis. Here, we demonstrate for the first time that direct contact of conditionally pathogenic bacteria with ejaculated human sperm may play an even greater role in the promotion of apoptosis than in case of some pathogenic bacterial strains. These findings suggest that significant bacteriospermia and leukocytospermia may be direct causes of subfertility or additional negative factors worsening the prognosis of fertility in natural and assisted procreation.

Novel Morphological Findings of Human Sperm Removal by Leukocytes in In Vivo and In Vitro Conditions: Preliminary Study

Biological significance of increased number of leukocytes in ejaculate remains a subject of controversy. The aim of this research was to describe the morphological characteristics of the sperm elimination by leukocytes in in vivo and in vitro conditions using natural stimulator of the immune system—uropathogenic Escherichia coli, O75:HNT, isolated from semen.

Chromatin structure analysis of spermatozoa from reciprocal chromosome translocation (RCT) carriers with known meiotic segregation patterns

The presence of reciprocal chromosome translocations (RCTs), as well as sperm chromatin disturbances, is known to exert negative influence on male fertility. The aim of this study was to identify an association between chromosome structural rearrangements in male RCT carriers and sperm seminological parameters (concentration, motility, morphology), chromatin status (fragmentation and maturity), meiotic segregation pattern and observed chromosomal hyperhaploidy. Sperm samples originated from ten male RCT carriers with reproductive failure/success. TUNEL assay (DNA fragmentation) and chromomycin A3 (CMA3)/aniline blue (AB) staining (chromatin maturity) were used to analyze sperm chromatin status while fluorescent in situ hybridization (FISH) was applied to observe meiotic segregation patterns and hyperhaploidy in spermatozoa. We found that the mean level of sperm DNA fragmentation in the RCT carrier group (18.0 ± 11.9%) was significantly higher (p=0.0006) than the mean of the control group (7.5 ± 4.3%). There was no correlation observed between sperm DNA fragmentation levels (5.6-38.0%) and the frequency of genetically normal/balanced gametes (34.3-62.4%), sperm seminological quality or revealed reproductive failure. In contrast, a correlation between the frequencies of genetically normal/balanced spermatozoa and of gametes with mature chromatin was observed (CMA3: R=0.4524, p=0.2604; AB: R=0.5238, p=0.1827). A statistically significant increase in the hyperhaploidy level of selected chromosomes in all analyzed RCT carriers was documented but was not correlated to sperm seminology or fertility status. Further evaluation and additional assays toward sperm chromatin quality assessment in RCT carriers is suggested to explain the complexity of genomic structural rearrangements and its possible relevance to reproductive success or failure.

Genetically modified human myoblasts with eNOS may improve regenerative ability of myogenic stem cells to infarcted heart

BACKGROUND Modern therapies of post infarcted heart failure are focused on perfusion improvement of the injured myocardium. This effect can be achieved by, among other means, implanting stem cells which could be genetically modified with factors inducing the formation of new blood vessels in the post infarction scar area. Combined stem cell and gene therapy seems to be a promising strategy to heal an impaired myocardium. The creation of new blood vessels can be indirectly stimulated via factors inducing vascular endothelial growth factor synthesis, for example endothelial nitric oxide synthase (eNOS). The product of this enzyme, nitric oxide, is a molecule that can influence numerous physiological activities; it can contribute to vasodilation, stimulation of endothelial cell growth, prevention of platelet aggregation and leukocyte adhesion to the endothelium. AIM To verify the pro-angiogenic and regenerative potential of human primary myoblasts and murine myoblast cell line C2C12 transiently transfected with eNOS gene. METHODS Stem cells (either human or murine) were maintained in standard in vitro conditions. Next, both types of myoblasts were modified using electroporation and lipofection (human and murine cells), respectively. The efficacy of the transfection method was evaluated using flow cytometry. The concentration of eNOS protein was measured by ELISA immunoassay. The biological properties of modified cells were assessed using an MTT proliferation test and DAPI cell cycle analysis. To verify the influence of oxidative stress on myoblasts, cytometric tests using Annexin V and propidium iodide were applied. To check possible alterations in myogenic gene expression of stem cells transduced by genetic modification, the myogenic regulatory factors were evaluated by real-time PCR. The function of genetic modification was confirmed by a HUVEC capillary sprouting test using myoblasts supernatants. RESULTS Electroporation turned out to be an efficient transfection method. High amounts of secreted protein were obtained (in the range 2,000 pg/mL) in both cell types studied. Moreover, the functionality of gene overexpression product was confirmed in capillary development assay. Human myoblasts did not exhibit any changes in cell cycle; however, eNOS transfected murine myoblasts revealed a statistically significant reduction in cell cycle ratio compared to controls (p < 0.001). In the case of myogenic gene expression, a decrease in Myogenin level was only detected in the human transfected myoblast population (p < 0.05). CONCLUSIONS The results of our study may suggest that transplantation of myoblasts overexpressing eNOS could be promising for cell therapy in regenerating the post infarction heart.

The effect of bacteriospermia and leukocytospermia on conventional and nonconventional semen parameters in healthy young normozoospermic males

Bacterial semen inflammation/infection is an important diagnostic and therapeutic problem in contemporary andrology. The molecular mechanism by which inflammatory mediators compromise the fertilizing potential of germ cells is complex and multifactorial, and it remains unclear. To improve the understanding of the pathophysiology of human subfertility/infertility caused or complicated by reproductive tract inflammation/infection, we simultaneously evaluated a set of conventional (standard semen analysis) and nonconventional sperm parameters, including subcellular changes in sperm membranes (phospholipid scrambling, peroxidative damage, and phosphatidylserine (PS) externalization), mitochondria (mitochondrial transmembrane potential, ΔYm, and oxidoreductive capability), and DNA fragmentation in healthy young normozoospermic males with asymptomatic bacteriospermia and leukocytospermia. Both bacteriospermia and leukocytospermia had a deleterious effect on standard sperm parameters, including sperm concentration, motility and morphology. Bacteriospermia was associated with a simultaneous decrease in mitochondrial transmembrane potential and an increase in PS externalization, and with DNA fragmentation in both live and dead sperm. The highest MDA concentrations in sperm lysates were observed in the presence of leukocytes. This study demonstrates for the first time that bacteriospermia and leukocytospermia compromise sperm quality in healthy young normozoospermic males. Bacteria mainly participate in intrinsic mitochondria-dependent apoptotic cell death mechanisms. Oxidative stress plays a relevant role in decreasing routine sperm parameters during leukocytospermia. The value of these observations may be significant and may support the development of a new diagnostic platform (biomarkers) for infertile males with infections in the reproductive tract.

Topology of chromosome centromeres in human sperm nuclei with high levels of DNA damage

Several studies have shown that the ‘poor’ sperm DNA quality appears to be an important factor affecting male reproductive ability. In the case of sperm cells from males with the correct somatic karyotype but with deficient spermatogenesis, resulting in a high degree of sperm DNA fragmentation, we observed changes in the preferential topology of the chromosome 7, 9, 15, 18, X and Y centromeres. The changes occurred in radial localization and may have been directly linked to the sperm chromatin damage. This conclusion is mainly based on a comparison of FISH signals that were observed simultaneously in the TUNEL-positive and TUNEL-negative sperm cells. The analyzed cells originated from the same ejaculated sample and FISH was performed on the same slides, after in situ TUNEL reaction. Based on the observed changes and previous data, it appears that the sperm nucleus architecture can be disrupted by a variety of factors and has a negative influence on spermatogenesis at the same time. Often, these factors coexist (e.g. chromosomal translocations, aneuploidies, a higher DNA fragmentation, abnormal seminology), but no direct correlations between the factors were observed.

Cytokines and Oxidative Stress in the Germ Line

Cytokines are important mediators of the immunologic response and involved in numerous physiological and pathological processes in the male genital tract. The same cytokines that act as elements of immunomodulation for the male gonad appear in large concentrations in semen in a number of pathological conditions, including autoimmune diseases, spinal cord injury, varicocele, or genital tract infection/inflammation. The activated macrophages and neutrophils release reactive oxygen intermediates and secrete proinflammatory cytokines, both of which can affect spermatozoa through peroxidative processes of sperm membrane components and DNA. Elucidation of these mechanisms and their interactions can be critical to develop novel diagnostic tests and treatment of male genital tract infection/inflammation. This chapter covers the current evidence about a relationship among the cytokines, antioxidants, prooxidants, and semen parameters.