Evaluation of beta-endorphin and interleukin-6 in seminal plasma of patients with certain andrological diseases

Immune regulatory cytokines in seminal plasma of healthy men: A scoping review and analysis of variance

OBJECTIVE

Seminal plasma cytokines are associated with fertility and reproductive health, but progressing their clinical utility is hampered by absence of reference data on concentration ranges of relevant cytokines in healthy men. We employed a systematic approach to assemble current evidence on the concentrations of immune regulatory cytokines present in seminal plasma (SP) of normozoospermic and/or fertile men and evaluated the impact of different platform methodologies for cytokine quantification.

EVIDENCE REVIEW

A systematic literature search was performed utilising PubMed, Web of Science and Scopus. Databases were searched from inception until 30th June 2022 inclusive, using combinations of keywords pertaining to seminal fluid and cytokines, and was restricted to human participants. Original data with values reported as concentration of specific cytokines in SP of men clearly defined as fertile or normozoospermic were extracted from studies written in English.

RESULTS

A total of 3769 publications were initially identified, of which 118 fulfilled the eligibility criteria for inclusion. A total of 51 individual cytokines are detectable in SP of healthy men. The number of studies reporting on each cytokine range from 1 to >20. The reported concentrations for many cytokines linked with fertility status, including IL6, CXCL8/IL8, and TNFA, are highly variable between published studies. This is associated with the different immunoassay methodologies utilised and may be exacerbated by a lack of validation of assays to ensure suitability for SP assessment. Due to the large variation between studies, accurate reference ranges for healthy men cannot be determined from the published data.

CONCLUSIONS

The concentrations of cytokines and chemokines detected in SP is inconsistent and highly variable between studies and cohorts, limiting current capacity to define reference ranges for cytokine concentrations in fertile men. The lack of standardisation in methods used to process and store SP, and variation in platforms used to evaluate cytokine abundance, are factors contributing to the observed heterogeneity. To progress the clinical utility of SP cytokine analysis will require standardisation and validation of methodologies so that reference ranges for healthy fertile men can be defined.

Serum interleukin-38 and -41 levels as candidate biomarkers in male infertility

BACKGROUND

Interleukin (IL)-38 and IL-41 are novel cytokines, but their role in male infertility (MI) is unknown. The purpose of this study was to measure the levels of serum IL-38 and IL-41 in patients with MI and correlate these levels with semen indexes.

METHODS

Eighty-two patients with MI and 45 healthy controls (HC) were recruited for this study. Semen parameters were detected using computer-aided sperm analysis, Papanicolaou staining, ELISA, flow cytometry, peroxidase staining and enzyme methods. Serum IL-38 and IL-41 levels were determined by ELISA.

RESULTS

Serum IL-38 levels were decreased (P < 0.01) in patients with MI compared with HC. Serum IL-41 levels were significantly higher in patients with MI than in HC (P < 0.0001). In patients with MI, serum IL-38 levels were positively correlated with semen white blood cell counts (r = 0.29, P = 0.009), and there was a positive correlation between semen white blood cell counts and sperm concentration (r = 0.28, P = 0.0100) and seminal plasma elastase (r = 0.67, P < 0.0001). Receiver operating characteristic curve analysis showed that the area under the curve of IL-38 for diagnosing MI was 0.5637 (P > 0.05), and the area under the curve of IL-41 for diagnosing MI was 0.7646 (P < 0.0001).

CONCLUSIONS

Serum IL-38 levels were significantly lower, and serum IL-41 levels were higher in patients with MI. These results suggest that IL-38 and IL-41 may be novel biomarkers for the diagnosis of MI.

Microbiology and immune mechanisms associated with male infertility

Up to 50% of infertility is caused by the male side. Varicocele, orchitis, prostatitis, oligospermia, asthenospermia, and azoospermia are common causes of impaired male reproductive function and male infertility. In recent years, more and more studies have shown that microorganisms play an increasingly important role in the occurrence of these diseases. This review will discuss the microbiological changes associated with male infertility from the perspective of etiology, and how microorganisms affect the normal function of the male reproductive system through immune mechanisms. Linking male infertility with microbiome and immunomics can help us recognize the immune response under different disease states, providing more targeted immune target therapy for these diseases, and even the possibility of combined immunotherapy and microbial therapy for male infertility.

Insight into oxidative stress in varicocele-associated male infertility: part 1

Varicocele is recognized as the leading cause of male infertility because it can impair spermatogenesis through several distinct pathophysiological mechanisms. Current evidence supports oxidative stress as a key element in the pathophysiology of varicocele-related infertility, although these mechanisms have not yet been fully described. Measurement of the reactive oxygen species and other markers of oxidative stress, including the levels of the antioxidant enzymes catalase and superoxide dismutase, can provide valuable information on the extent of oxidative stress and might guide therapeutic management strategies. The testis can respond to varicocele-associated cell stressors, such as heat stress, ischaemia or production of vasodilators (for example, nitric oxide) at the expense of the generation of excessive reactive oxygen species. These responses have their own implications in exacerbating the underlying oxidative stress and on the subsequent infertility.

Elevated body mass index correlates with higher seminal plasma interleukin 8 levels and ultrasonographic abnormalities of the prostate in men attending an andrology clinic for infertility

BACKGROUND

Obesity is associated with a systemic, low-grade inflammatory state. Although the relationship between obesity and semen parameters or prostate diseases has been previously investigated, the association between body mass index (BMI), prostate inflammatory diseases and color- Doppler ultrasound (CDU) of the male genital tract (MGT) has been poorly studied.

AIM

To evaluate the association between BMI and CDU features of the MGT, signs and symptoms of prostate inflammation, semen parameters.

MATERIALS/SUBJECTS AND METHODS

We studied 222 men seeking medical care for couple infertility. According to the World Health Organization classification, subjects were divided into 3 groups: normal weight (no.=131, BMI=18.5-24.9 kg/m2), overweight (no.=71, BMI=25.0-29.9 kg/m2), obese (no.=20, BMI≥30.0 kg/m2). All patients underwent simultaneous testosterone evaluation and seminal analysis, including interleukin 8 (sIL-8), along with scrotal and transrectal CDU, before and after ejaculation. Prostatitis symptoms were evaluated by National Institutes of Health- Chronic Prostatitis Symptom Index questionnaire.

RESULTS

After adjusting for age and testosterone levels, higher BMI was significantly related to higher prostate volume and several CDU features of the prostate, including macro-calcifications, inhomogeneity, higher arterial peak systolic velocity (the latter adjusted also for blood pressure), but not with abnormalities of testis, epididymis, seminal vesicles. Furthermore, higher BMI and BMI class were significantly related to higher sIL-8, a reliable surrogate marker of prostate inflammatory diseases, even after adjustment for age. Conversely, no associations among BMI, clinical symptoms of prostatitis or semen parameters were observed.

CONCLUSIONS

Subjects with higher BMI might develop CDU and biochemical signs suggestive of prostate inflammation, although not clinically overt.

Levels of interleukin-6 and interleukin-8 in seminal fluid of men attending an andrological clinic

The presence of interleukins (IL) and other cytokines in seminal plasma was demonstrated in the literature. In particular, the levels of IL-6 were found to be related to male accessory gland inflammation. The close correlation to leucocyte count indicates a production of interleukins from the leucocytes and by the prostate gland. No relation of IL-6 levels to spermatogenic activity was quoted in the literature. We measured IL-6 and IL-8 in 454 men and compared the values with seminal parameters. The mean values of IL-6 30.7 +/- 101.2 pg ml-1 and IL-8 2023 +/- 1721 pg ml-1. The correlation analysis revealed a significant correlation of IL-6 and/or IL-8 to age, total fructose, immunoglobulin G (IgG) concentration and leucocyte count. The significant correlation of IL-6 and fructose levels indicates that also the seminal vesicles take part in the production of seminal IL-6. No correlation of the two interleukins measured to sperm parameters occurred. The calculation of a single harmonic trend revealed a significant trend over the year of the levels of IL-6 with a maximum in December and a peak-to-trough variation of 33% of the mean. It may be the consequence of a higher frequency of seminal tract inflammations in autumn and winter.

Relation between immunosuppressive PGE(2) and IL-10 to pro-inflammatory IL-6 in seminal plasma of infertile and fertile men

In vitro studies have reported that seminal plasma of fertile men has more inhibitory mitogenic effect and higher suppressive activity on antibody-dependent cellular cytotoxicity than seminal plasma from infertile males. Is it possible that variations in the seminal plasma composition could explain these results? The present study was conducted to investigate the relation between immunosuppressive PGE(2) and IL-10 to pro-inflammatory IL-6 in seminal plasma of infertile and fertile men. Utilizing specific ELISA commercial kit, semen samples from 45 infertile undiagnosed and 25 fertile men were examined for the presence of PGE(2), IL-10, and IL-6. The IL-6 concentration in seminal plasma of infertile men was significantly higher than that of fertile men (p<.0 4). However, levels of IL-10 were lower for the semen of infertile men than that of fertile men (p<.04). No differences were observed in PGE(2) concentrations between both groups. Increase in pro-inflammatory cytokines, such as IL-6, and decrease in immunosuppressive ones, such as IL-10, could alter the tolerance to sperm cell in male and female tracts and reduce the favorable conditions to reach the fecundation and implantation. It is necessary to conduct further studies that include other pro- and anti-inflammatory substances to evaluate the importance of the immune balance of semen in human fertility.

Detection of fractalkine in human seminal plasma and its role in infertile patients

BACKGROUND

Fractalkine is a relatively newly discovered CX(3)C chemokine, which is a chemoattractant for T cells, monocytes and natural killer cells. Several reports have demonstrated the association between chemokine levels in seminal plasma and semen quality. The fractalkine levels in ejaculates from normal donors and infertile male patients with or without asthenozoospermia, were examined and correlated with sperm motility and morphology.

METHODS AND RESULTS

Western blot analysis showed fractalkine protein to be present in the seminal plasma. Fractalkine titres in the seminal plasma of infertile men with asthenozoospermia (0.64 +/- 0.04 microg/ml; n = 58) were lower than those in patients without asthenozoospermia (0.94 +/- 0.10 microg/ml; n = 22, P < 0.01) and fertile donors (1.04 +/- 0.07 microg/ml; n = 10, P < 0.001). There was no significant difference between fractalkine levels in patients with and without leukospermia. No significant correlation was found between fractalkine and interleukin-8 levels in seminal plasma. Sperm motility was positively correlated (R(2) = 0.14, P < 0.001) with fractalkine concentration. The existence of CX(3)CR-positive leukocytes in semen was confirmed using specific primers for CX(3)CR.

CONCLUSIONS

These results suggest that fractalkine is a chemokine associated with sperm motility and the migration of CX(3)CR-positive leukocytes into semen.

A repertoire of cytokines in human seminal plasma

The pathophysiological significance of seminal cytokines in sperm function is still controversial. We determined the repertoire of cytokines in seminal plasma obtained from men with or without abnormalities in semen and assessed the pathophysiological significance of seminal cytokines. After conventional analysis of semen samples obtained from 86 men, levels of seminal cytokines (interleukin [IL]-1alpha, IL-2, IL-4, IL-6, IL-8, tumor necrosis factor-alpha [TNF-alpha], interferon-gamma, granulocyte colony-stimulating factor [G-CSF], macrophage CFS [M-CSF]) and granulocyte elastase were measured by an enzyme-linked immunosorbent assay. Leukocytospermia was defined as seminal plasma, which has > or =1000 ng/ml granulocyte elastase. Leukocytospermia was found in nine of 62 of the subjects in the normozoospermic group but in none of the 24 subjects showing abnormal sperm parameters (azoospermia, n=5; oligozoospermia, n=4; asthenozoospermia, n=15). The IL-8 level in the leukocytospermic group was significantly higher than those in the normal and oligozoospermic groups. IL-1alpha and TNF-alpha levels in the leukocytospermic group were significantly higher than those in the normal and asthenozoospermic groups. Although the G-CSF level in the leukocytospermic group was significantly higher than that in the normal group, high levels of M-CSF were detected in all groups. The IL-8 level was strongly correlated with IL-1alpha (r=0.935, P<0.0001) and G-CSF (r=0.916, P<0.0001) levels. Cytokines detected in seminal plasma are associated with the pathogenesis of leukocytospermia but not with the pathogenesis of asthenozoospermia and oligozoospermia.

Correlation of beta-endorphin and prostaglandin E2 levels in prostatic fluid of patients with chronic prostatitis with diagnosis and treatment response

PURPOSE

The chronic pelvic pain syndrome is a clinically defined symptom complex of unclear etiology. We have noted increased oxidative stress in the prostatic fluid of these patients, implying an active inflammatory response. Immune cells can produce the natural opioid beta-endorphin at the site of injury, which may modulate pain. We measured beta-endorphin and the inflammatory marker prostaglandin E2 in the expressed prostatic secretions of men with prostatitis, and correlated the results with symptoms.

MATERIALS AND METHODS

Expressed prostatic secretions samples from 70 patients and 8 asymptomatic controls were collected and frozen. beta-Endorphin and prostaglandin E2 were measured by enzyme-linked immunosorbent assay. Results were stratified according to prostatitis category and compared in individuals before and after therapy.

RESULTS

In symptomatic patients beta-endorphin and prostaglandin E2 were not significantly different in categories II, IIIa and IIIb expressed prostatic secretions but they were higher than in controls. The mean beta-endorphin level plus or minus standard error of mean in symptomatic patients was significantly higher (23.8 +/- 11 ng./ml. versus 8.7 +/- 4.7, p = 0.0001) and mean prostaglandin E2 was lower (6.01 +/- 2.9 ng./ml. versus 3.01 +/- 2.9, p = 0.001) after successful therapy with antibiotics or antioxidant phytotherapy, Prosta-Q (Farr Laboratories, Santa Clarita, California).

CONCLUSIONS

We observed a correlation of higher prostaglandin E2 and lower beta-endorphin in symptomatic men with chronic prostatitis. Increased oxidative stress and inflammation may induce prostaglandin E2 production that would inhibit beta-endorphin release. Treatment with therapeutic agents that decrease oxidative stress, such as antibiotics and antioxidant phytotherapy, may function at least partially by increasing beta-endorphin and decreasing prostaglandin E2.

Interleukin-6 (IL-6) in seminal plasma of infertile men, and lipid peroxidation of their sperm

Concentrations of tumor necrosis factor-alpha (TNF-alpha) and interleukin-6 (IL-6) in seminal fluid, as well as levels of sperm lipid membrane peroxidation, were investigated in fertile and infertile men. Semen samples, obtained by masturbation from 37 infertile and 14 fertile men, were examined for the presence of TNF-alpha and IL-6. The level of lipid peroxidation of the sperm membrane was measured by determining malondialdehyde (MDA) formation. The correlation between the IL-6 and the TNF-alpha concentrations in seminal plasma with the levels of lipid peroxidation of the sperm membranes was statistically evaluated. The IL-6 concentration in seminal plasma of infertile men was significantly higher than that of fertile men (p < .05). Similarly, the level of membrane lipid peroxidation was higher for the semen of infertile men than that of fertile men (p < .001). A significant positive correlation was found between IL-6 levels in seminal plasma and membrane sperm lipid peroxidation (p < .002), but not between this parameter and TNF-alpha levels in seminal plasma. These findings suggest a possible association between IL-6 seminal plasma levels and lipid peroxidation of sperm membrane. Stimulation of reactive species production by human sperm and leucocytes, induced by the high levels of IL-6, could explain these results.

Mechanisms of sperm deficiency in male accessory gland infection

The presence of 2 million or more peroxidase-positive white blood cells per ml of semen, or the diagnosis of male accessory gland infection, is associated with important biochemical and biological changes in semen plasma and in the spermatozoa, reducing their fertilizing potential in vitro and in vivo (e.g., during intra-uterine insemination). In addition to the effects of reactive oxygen species, and its influence on the essential fatty acid composition of the sperm membrane, potentially unfavourable effects can occur through the intermediate of increased concentrations of certain cytokines, and decreased activity of enzymes such as alpha-glucosidase. In contrast, lower numbers of white blood cells may exert beneficial effects on spermatozoa thanks to the increased production of hepatocyte growth factor/scatter factor (a tissue repairing substance), and the stimulation of immuno-competent cells by particular cytokines (e.g., Interleukin-6).

Patient assessment in chronic prostatitis

Assessment of men suffering from proven chronic prostatitis involves a cascade of diagnostic steps, including evaluation of symptoms and clinical features, objectivation of the inflammatory response in expressed prostatic secretions, standardized localization techniques for common bacteria and a search for fastidious, uncommon pathogens.

Vectorial production of interleukin 1 and interleukin 6 by rat Sertoli cells cultured in a dual culture compartment system

The bidirectional production of interleukin-1 (IL-1) and IL-6 by Sertoli cells and its regulation by inflammatory and physiological stimuli has been studied using a dual compartment culture system allowing the study of Sertoli cell apical and basal secretory activities. Another Sertoli cell activity, the vectorial transferrin production was also studied in all culture conditions. A low constitutive IL-1 production appeared equally distributed between both poles, while IL-6 and transferrin constitutive production was predominantly directed apically. Two activators of macrophages, lipopolysaccharides and zymosan, were found to induce marked increases of IL-1 in the compartment where they had been added: basal if added to the lower compartment and vice versa. In contrast, after a basal stimulation, IL-6 production was mainly increased in the upper compartment that corresponds to a Sertoli cell apical flux. In this system, IL-1 and IL-6 levels were not modified by FSH; they were not also affected by residual bodies and latex beads, probably due to the fact that, in the bicameral system, phagocytosis is restricted to the Sertoli cells situated at the surface of the inner compartment. IL-1beta, but not IL-1alpha, induced IL-6 secretion in the compartment of stimulation. In conclusion, the present study demonstrates that vectorial secretory patterns of IL-1 and IL-6 production greatly differ and that these cytokines are also differently regulated. These results suggest that Sertoli IL-1 and IL-6 have different targets within the testis and that, in normal and pathophysiological conditions, both the tubular and the interstitial compartments may be influenced by the action of these paracrine factors.

Endogenous opiates: 1995

This article is the eighteenth installment of our annual review of research concerning the opiate system. It includes articles published during 1995 reporting the behavioral effects of the opiate peptides and antagonists, excluding the purely analgesic effects. The specific topics covered this year include stress: tolerance and dependence; eating; drinking; gastrointestinal, renal, and hepatic function; mental illness and mood; learning, memory, and reward; cardiovascular responses; respiration and thermoregulation; seizures and other neurological disorders; electrical-related activity; general activity and locomotion; sex, pregnancy, and development; immunological responses; and other behaviors.