Chronic epididymitis and leptin and their associations with semen characteristics in men with infertility

Leptin affects spermatogenic function via activation of the Akt/ERK/AMPK signaling pathway

BACKGROUND

Obesity is often associated with elevated leptin levels and leptin resistance, which can lead to impaired reproductive function. While exogenous leptin is known to enhance reproductive capacity in leptin-deficient male mice, its effects on reproductive function in obese male mice and the underlying mechanisms remain unclear. This study aims to elucidate the effects of leptin on testicular tissue, semen, and associated signaling pathways in both normal and obese male mice.

METHODS

A high-fat diet-induced obesity model was established in male C57BL/6 J mice, followed by the administration of exogenous leptin. Histological changes in testicular tissue were observed using HE staining, while RT-PCR was employed to investigate mRNA expression levels of leptin and its receptor. The expression of proteins involved in leptin-related signaling pathways was analyzed by Western blotting.

RESULTS

Both high-fat diet-induced obesity and exogenous leptin administration led to significant alterations in testicular histomorphology, semen parameters, and reproductive hormones, ultimately impairing fertility. Leptin intervention significantly decreased FSH and LH levels, along with a reduction in serum leptin levels and the expression of leptin and its receptor mRNA. Moreover, exogenous leptin promoted the phosphorylation of STAT3, ERK, and AMPK, suggesting activation of these signaling pathways.

CONCLUSIONS

Normal mice exhibited negligible responses to exogenous leptin, whereas obese mice showed significant leptin resistance, likely due to the opposing signaling pathways that modulate leptin's effects. This study highlights the differential impact of leptin on reproductive function between normal and obese mice, with leptin resistance in obese mice potentially serving as a protective mechanism against reproductive damage.

Presence of leptin and its receptor in the ram reproductive system and in vitro effect of leptin on sperm quality

Leptin is a 16 kDa hormone encoded by obese (OB) gene in adipocytes. This molecule not only regulates energy metabolism but also plays a role in the reproduction of mammals. Leptin and its receptor (OBR) have been found in male reproductive systems of human, bovine, equine and pig. The effects of leptin on sperm quality vary widely from different research findings. However, the presence of leptin and its receptor in the ram reproductive system and the in vitro effect of leptin on sperm quality have not reported yet. In the present study, we found that the OB was highly expressed in primary and secondary spermatocytes of the testes, OBR was highly expressed in secondary spermatocytes of the testes. The expressions of OB were in stereocilia of epididymis and in columnar cells of epididymal caput and cauda, the expressions of OBR were in columnar cells of epididymis and in stereocilia of epididymal corpus and cauda. The presence of both OB and OBR in testes, epididymis and sperm were confirmed through RT-PCR, immunolocalization and Western blot analyses. The RT-qPCR results indicated OB and OBR had higher expression levels in epididymal sperm than that of the ejaculated sperm in rams. When sperm were treated with 5 ng/mL leptin, the progressive motility (P < 0.01), straight-line velocity (VSL) (P < 0.05), average path velocity (VAP) (P < 0.05), membrane mitochondrial potential (MMP) (P < 0.01) and viability (P < 0.05) significantly increased, while DNA fragmentation index (DFI) and reactive oxygen species (ROS) significantly decreased compared to the control (P < 0.01), and the other semen parameters such as acrosome integrity and acrosome reaction rate had no significant changes between groups (P > 0.05). In conclusion, this is probably the first report describing localization of leptin and its receptors in the reproductive system of rams and their effects on sperm quality parameters. Our findings suggest that 5 ng/mL leptin treatment enhanced sperm motility, viability and MMP, and decrease DFI and ROS without obvious influence on the acrosome reaction in ram sperm. The potential mechanisms may be related to leptin's ability to reduce the oxidative stress and apoptosis of sperms and improve their mitochondrial function and energy supply, therefore, to maintain the physiological homeostasis of the sperm.

Systematic Review of Literature Documenting the Link Between BMI, Sperm Parameters, and Leptin

Background: Leptin administration to rats causes adverse effects on sperm that resemble those reported in obese males. The purpose of this review is, therefore, to examine whether human and animal studies have taken this information on board and have attempted to link the poor sperm quality in obese or overweight individuals to leptin in their methodology, data analysis, and discussion. The review also documents the link between low sperm quality in the obese and leptin.

Method: A search was made for articles reporting body mass index (BMI), sperm parameters, and leptin, published until September 2020 in PubMed, Science Direct, Google Scholar, and Springer Link using a number of search terms.

Results: Forty-four of the 53 human and animal studies on BMI and sperm parameters reported abnormal sperm parameters in the obese but only 9 of those had measured serum leptin. None, however, attempted to link sperm abnormalities to leptin. Nine animal studies report of adverse effects of leptin on sperm in normal weight rats that were found to be similar to those reported in obese males.

Conclusion: Although none of the human studies had actually linked the raised leptin to sperm abnormalities in the obese, there is nevertheless, convincing evidence linking leptin to obesity-related poor sperm quality and male infertility. There is a need, therefore, to include measures that will help reduce the impact of raised leptin levels on male reproductive function, particularly, in obese infertile or subfertile males.

Increase of leucocyte-derived extracellular traps (ETs) in semen samples from human acute epididymitis patients-a pilot study

PURPOSE

To study the effector mechanism against pathogens of polymorphonuclear neutrophils (PMN) and macrophages, called ETosis, involving the release of extracellular traps (ETs) in patients with acute epididymitis. To assess the different ET phenotypes present in semen samples and to identify correlations between ETosis and clinical parameters.

MATERIALS AND METHODS

Samples from patients diagnosed with acute epididymitis were examined and compared with samples from uninfected controls. Biochemical analyses of seminal fluid included determination of peroxidase, α-glucosidase, fructose, and elastase levels. ETosis in semen was determined through presence of citrullinated histones, global histones, and extracellular DNA. Different ETosis phenotypes such as spread ETs, aggregated ETs, and diffuse ETs were identified by co-localisation of extruded DNA with myeloperoxidase and global histones. Anti-CD15⁺ and anti-CD68⁺ antibodies were used to identify different cell lines.

RESULTS

Revealed a high number of ETs compared with the control group. The mean number of CD15⁺PMN and CD68⁺ macrophages was higher in the acute epididymitis group. ETosis increase in ejaculates correlated with clinical parameters such as enhancement of elastase concentrations and diminution of fructose in the semen.

CONCLUSIONS

This work shows for the first time the presence of ETs and their components in semen from patients with acute epididymitis. The presence of infections is an important factor for induction of ETs in semen. Furthermore, the presence of ETosis in ejaculates is suggestive of developing infectious processes and might possibly have a diagnostic value.

Challenges in the diagnosis of testicular infarction in the presence of prolonged epididymitis: Three cases report and literature review

INTRODUCTION

Testicular infarction is a rare complication of prolonged epididymitis and may be misdiagnosed as testicular torsion. In this study, we present three cases of testicular infarction and discuss their clinical characteristics, imaging features and clinical management.

PATIENTS AND METHODS

Three adult males with prolonged epididymitis presented with chronic unilateral testicular pain, tenderness, and palpable swelling, including left varicocele in one case and hydrocele in the other two cases. Patient's symptoms were not relieved after antibiotic therapy. We analyzed the diagnosis, management, and outcome of these three cases of testicular infarction resulting from prolonged epididymitis. This includes the clinical characteristics, features of color doppler ultrasound imaging for diagnosis, and treatment strategy for testicular infarction from prolonged epididymitis.

RESULTS

Complete blood count (CBC) indicated a small leukocytosis (10.6±0.4×109/L; normal arrange 3.5-9.5 WBC×109/L). Color doppler images demonstrated appropriate blood flow to areas of interest at patient's initial visit. At follow up visit several months later, the increased blood flow was detected at the edges of the involved testes with no blood flow to the center. The sizes of the involved testis (27±4 ml) was significantly larger compared to the non affected side (17±2 ml) (p < 0.05). Unilateral simple orchiectomy was performed on the involved testis in all three cases. Grossly, abscess cavities with caseous necrosis were found at the center of the testicle and epididymis in two patients. Histopathologic examination showed chronic inflammation with lymphocytic and macrophage infiltration of the involved testicle in two cases. The third case stained positive for acid fast bacteria. Left varicocele disappeared postoperatively in one patient. No pain, wound infection or other discomfort were noted 12 months after surgery.

COMMENTS

This series revealed that testicular infarction may result from inappropriately treated prolonged epididymitis. Epididymal tuberculosis should be considered in cases with epididymitis not responding to broad spectrum antibiotics. Testicular infarction induced by prolonged epididymitis is easily missed due to a lack of symptom changes. Color doppler images are helpful in the diagnosis. This usually presents as a decrease in blood flow at the center of the testis with the increased flow at the periphery differentiating this from testicular torsion.