Evaluation of Fas positive sperm and complement mediated lysis in subfertile individuals

Role of T cell-induced autoimmune response in the pathogenesis of glaucoma

PURPOSE

This review aims to elucidate the role of T cell-induced autoimmune responses in the pathogenesis of glaucoma, focusing on the immunological changes contributing to retinal ganglion cell (RGC) damage.

METHODS

A comprehensive review of recent studies examining immunological mechanisms in glaucoma was conducted. This included analyses of T cell interactions, heat shock proteins (HSPs), and resultant autoimmune responses. Key findings from experimental models and clinical observations were synthesized to present a coherent understanding of immune dynamics in glaucoma.

RESULTS

Glaucoma is a neurodegenerative disease marked by optic nerve atrophy and irreversible vision loss due to RGC damage. The disease is etiologically heterogeneous, with multiple risk factors and pathogenic mechanisms. Recent research highlights the dual immunomodulatory role of T cells in immune protection and injury. T cells, pre-sensitized by bacterial HSPs, can cross-react with endogenous HSPs in RGCs under stress, leading to autoimmune damage. Elevated levels of HSP autoantibodies and abnormal T cell activity have been observed in glaucoma patients, indicating a significant autoimmune component in disease progression.

CONCLUSIONS

T cell-induced autoimmune responses are crucial in the pathogenesis of glaucoma, contributing to RGC degeneration beyond the effects of elevated intraocular pressure. Understanding these immunological mechanisms is vital for developing targeted neuroprotective therapies for glaucoma.

Expression of proapoptotic receptors Fas/Fas-L on sperm cells and levels of their soluble forms in seminal fluid from patients with varicocele

Varicocele is a condition in which the pampiniform venous plexus in the scrotum dilates abnormally during puberty, affecting testicular growth and semen parameters, and is thought to be a major cause of male infertility. The findings of researches on the presence of the Fas system in sperm are controversial. As the main triggers of apoptosis in the semen of patients with varicocele, in this study, we examined the expression of Fas/Fas-L on sperm cells and also the levels of their soluble forms in seminal plasma. Semen samples were taken from 45 patients with varicocele (study group) and 45 healthy subjects without varicocele (control group) after 3-5 days of ejaculatory abstinence. Flow cytometry was used to examine the expression of Fas and Fas ligand (Fas-L) on Sperm cells. Furthermore, soluble Fas (sFas) and soluble Fas-Ligand (sFas-L) levels in the seminal fluid were determined using an ELISA (enzyme-linked immunosorbent assay). The presence of Fas and Fas-L proteins on the sperm ejaculation surface was not found in the patients with varicocele or the control groups. However, in the case group (3.32 ± 0.31 ng/mL), sFas seminal concentrations were slightly lower than in the control group (5.50 ± 0.36 ng/mL) (p < 0.001). In varicocele patients, there was a strong negative association between seminal sFas and sperm motility. Apoptosis effects through this system on key sperm parameters were not found based on our findings. In varicocele, a reduction in sperm count and motility does not seem to be due to Fas-related mechanisms, but rather to other mechanisms.

Relationship between fertilization rate and early apoptosis in sperm population of infertile individuals

Integrity of the sperm membrane, of which phosphatidyl serine (PS) plays a central role, is essential for fertilization. The externalisation of PS (EPS) occurs during capacitation and the acrosome reaction. EPS, from the inner to the outer membrane, is considered as a sign of early apoptosis. Therefore, EPS may have a dual function in sperm. This study has evaluated the relationship between EPS and fertilization, embryo quality and pregnancy outcomes in couples who were candidates for ICSI. Semen samples were collected from 43 ICSI candidates and assessed according to World Health Organization guidelines for semen parameters. EPS was assessed by Annexin V and propidium iodide (PI) staining. Protamine deficiency was assessed by chromomycin A3 (CMA3) staining. A significant positive correlation was observed between the percentages of fertilization and annexin-positive PI-negative (An(+)PI(-)) sperm. There was a significant negative correlation between the percentages of protamine-deficient sperm with the percentage of fertilization. In addition, the percentage of An(+)PI(-) sperm in individuals with fertilization rates higher and lower than 50% significantly differed. The percentage of annexin-positive PI-positive (An(+)PI(+)) sperm in semen of the partners of pregnant women significantly differed from the partners of nonpregnant women. In conclusion, if An(+)PI(-) is a sign of capacitation and An(+)PI(+) is a sign of apoptosis, the results suggest that semen samples with a higher ability to undergo capacitation have a higher chance to result in successful fertilization post-ICSI. The presence of a high percentage of apoptotic sperm in the insemination sample before capacitation may reduce the chances of pregnancy.

Origin and role of DNA damage in varicocele

Varicocele is considered as one of the main etiologies of male infertility. Along with altered semen parameters, increased DNA fragmentation is believed to play an important role in varicocele-induced infertility. DNA damage may result from intra- or extra-testicular factors. Among these, apoptosis, abnormal chromatin packaging and oxidative stress are the most researched and are addressed in this review. Significant evidence suggests that varicoceles have a harmful effect on testicular function and a varicocelectomy not only prevents progressive decline in testicular function, but also reverses the damage. However, the degree to which varicocele repair improves pregnancy rates and the success of assisted reproductive technology (ART) remains controversial. Therefore, the role of varicocele repair on DNA fragmentation is also discussed.

Sperm DNA integrity assays: diagnostic and prognostic challenges and implications in management of infertility

Sperm is not a simple carrier of paternal genetic information but its role extends clearly beyond fertilization. Integrity of sperm genome is an essential pre-requisite for birth of healthy offspring and evaluation of sperm should entail DNA integrity analysis. DNA integrity analysis is a better diagnostic and prognostic marker of sperm reproductive potential. Conventional semen analysis emphasizes on sperm concentration, viability, motility and morphology and has been proven to be a poor indicator of reproductive potential and pregnancy outcome. To overcome the drawbacks associated with conventional semen analysis more useful fertility tests and molecular biomarkers have been explored. Among the different tests which have evolved for assessing the sperm reproductive potential, tests for sperm DNA quality are most promising. Sperm DNA damage has been closely associated with numerous indicators of reproductive health including fertilization, embryo quality, implantation, spontaneous abortion, congenital malformations and childhood diseases. It therefore has great potential as a prognostic test for both in vitro and in vivo conception. This review presents an updated account of tests that have better diagnostic and prognostic implications in the evaluation of sperm DNA damage. The basic principles, outline of methodology, advantage, disadvantage, clinical significance of each technique and implications of these tests have been discussed. The logistics of each test with respect to available resources and equipment in an andrology laboratory, the feasibility of performing these tests in routine diagnostic workup of infertile men and the opportunities and challenges provided by DNA testing in male fertility determination are also presented.