The possible role of sirtuins in male reproduction.

Global influence of male infertility is increasing in recent decades. Proper understanding of genetics, anatomy, physiology and the intricate interrelation of male reproductive system are much needed for explaining the etiology of male infertility; and a detailed study on the epigenetics, indeed, will reveal the molecular mechanism behind its etiology. Sirtuins, the molecular sensors, are NAD+ dependent histone deacetylases and ADP- ribosyl transferases, participate in the chief events of epigenetics. In mammals, sirtuin family comprises seven members (SIRT1-SIRT7), and they all possess a conserved NAD+ binding catalytic domain, termed the sirtuin core domain which is imperative for their activity. Sirtuins exert a pivotal role in cellular homeostasis, energy metabolism, apoptosis, age-related disorders and male reproductive system. However, their exact role in male reproduction is still obscure. This article specifically reviews the role of mammalian sirtuins in male reproductive function, thereby, prompting further research to discover the restorative methods and its implementation in reproductive medicine.

The Role of LIM Kinase in the Male Urogenital System.

The LIM kinases (LIMK1 and LIMK2), known as downstream effectors, and the Rho-associated protein kinase (ROCK), a regulator of actin dynamics, have effects on a diverse set of cellular functions. The LIM kinases are involved in the function of the male urogenital system by smooth muscle contraction via phosphorylation of cofilin and subsequent actin cytoskeleton reorganization. Although LIMK1 and LIMK2 share sequence similarities as serine protein kinases, different tissue distribution patterns and distinct localization during cell cycle progression suggest other biological functions for each kinase. During meiosis and mitosis, the LIMK1/2-cofilin signaling facilitates the orchestrated chromatin remodeling between gametogenesis and the actin cytoskeleton. A splicing variant of the LIMK2 transcript was expressed only in the testis. Moreover, positive signals with LIMK2-specific antibodies were detected mainly in the nucleus of the differentiated stages of germ cells, such as spermatocytes and early round spermatids. LIMK2 plays a vital role in proper spermatogenesis, such as meiotic processes of spermatogenesis after puberty. On the other hand, the literature evidence revealed that a reduction in LIMK1 expression enhanced the inhibitory effects of a ROCK inhibitor on the smooth muscle contraction of the human prostate. LIMK1 may have a role in urethral obstruction and bladder outlet obstruction in men with benign prostatic hyperplasia. Moreover, LIMK1 expression was reduced in urethral stricture. The reduced LIMK1 expression caused the impaired proliferation and migration of urethral fibroblasts. In addition, the activated LIMK2-cofilin pathway contributes to cavernosal fibrosis after cavernosal nerve injury. Recent evidence demonstrated that short-term inhibition of LIMK2 from the immediate post-injury period prevented cavernosal fibrosis and improved erectile function in a rat model of cavernosal nerve injury. Furthermore, chronic inhibition of the LIMK2-cofilin pathway significantly restrained the cavernosal veno-occlusive dysfunction, the primary pathophysiologic mechanism of post-prostatectomy erectile dysfunction through suppressing fibrosis in the corpus cavernosum. In conclusion, the LIM kinases-cofilin pathway appears to play a role in the function of the male urogenital system through actin cytoskeleton reorganization and contributes to the pathogenesis of several urogenital diseases. Therefore, LIM kinases may be a potential treatment target in urogenital disorder.

Novel nucleotide insertions in two unrelated Indian patients with 5α reductase 2 deficiency leading to premature termination of SRD5A2 enzyme.

T is converted to a more potent androgen, DHT by the action of microsomal membrane enzyme 5α reductase 2. Defects in 5α reductase 2 isozyme results in incomplete virilisation of external male genitalia. Mutations in SRD5A2 gene leads to diminished enzyme activity, thus hampering DHT synthesis from T. We describe two unrelated patients from India with 5αRD2 due to novel insertion of nucleotides in the exon 1 of SRD5A2 gene that lead to premature termination of protein. Master S (case 1; III.8) was 3 years old at initial evaluation, had perineoscrotal hypospadias, microphallus and both testes were palpable in the inguinal region. Master P (case 2; III.9) was born as normal full term baby. He had primary complaint of microphallus, penoscrotal hypospadias and gonads in the inguinal region. Diagnosis of 5αRD2 was made, as T/DHT ratio in the two cases was 41 and 131.2 respectively. Sequence analysis of SRD5A2 gene showed an insertion of nucleotides TA in exon 1 (c.188_189). This resulted in premature termination of the protein due to stop codon at amino acid position 7. The protein formed is drastically truncated and inadequate protein synthesized explains the phenotypic characteristics of our patients.

Selective inhibition of PDE4 in Wistar rats can lead to dilatation in testis, efferent ducts, and epididymis and subsequent formation of sperm granulomas.

Testicular tubular dilatation and degeneration and epididymal sperm granulomas were frequently seen in 4-week toxicity studies using different phosphodiesterase-4 (PDE4) inhibitors in Wistar rats, including the prototypic PDE4 inhibitor BYK169171. To investigate the pathogenesis of testicular and epididymal lesions, a time course study with BYK169171 was conducted with sequential necropsies after 7, 14, 21, and 28 days of treatment. After 7 days, a dilatation of efferent ducts and of the initial segment of the epididymis and a subacute interstitial inflammation were seen followed by a diffuse dilatation of seminiferous tubules in the testis. Dilatation and inflammation were most pronounced after 14 days. Single animals also exhibited vascular necrosis in the inflamed interstitium. Although dilatation decreased later in the study, the incidence and severity of tubular degeneration increased from 14 days onward. Sperm granulomas developed in efferent ducts and in the caput and cauda of the epididymis after 14 days. Our results demonstrate a clear time course of PDE4 inhibition-induced lesions, with dilatation preceding sperm granuloma formation. We conclude that the most likely mechanism of toxicity is a disturbance of fluid homeostasis in efferent and epididymal ducts resulting in abnormal luminal fluid and sperm contents, epithelial damage at specific sites of the excurrent duct system, sperm leakage, and granuloma formation.

Age-related changes in seminal polymorphonuclear elastase in men with asymptomatic inflammation of the genital tract.

AIM: To investigate age-related inflammatory events in the male genital tract. METHODS: In a total of 4265 randomly collected patients attending the andrological outpatient clinic of the Center for Dermatology and Andrology, University of Giessen, Germany, ejaculate volume, pH-value, sperm concentration, total and progressive sperm motility, concentration of polymorphonuclear (PMN) elastase, number of peroxidase-positive cells and fructose were measured and correlated with patient's age. RESULTS: While ejaculate volume, motility and fructose all correlated negatively with age, sperm concentration, PMN elastase and the pH-value showed a positive correlation. The prevalence of male genital tract inflammation (as defined by PMN elastase > 250 ng/mL) and its severity increased significantly. PMN elastase did not correlate with sperm motility. Fructose as a marker of seminal vesicle function showed a significant negative relationship with the PMN elastase levels, the number of peroxidase-positive cells and sperm motility. CONCLUSION: The significant increases of PMN-elastase levels as marker of male genital tract inflammation in older men appear to be indicative of age-related changes in local immunoregulatory mechanisms. Because there is no association of PMN elastase with sperm motility, a direct inhibitory effect of this enzyme can be excluded.

[Sperm biochemical markers of genital tract inflammation: usefulness of elastase determination]. / Marqueurs biochimiques du sperme à la recherche de l'inflammation génitale: intérêt de la détermination de l'élastase.

Genital tract inflammation was for a long time suspected of inducing sterility in the male. The role of leukocytes in sperm changes is still debated. The identification of inflammation is based on the presence of activated leukocytes and the elastase measurement. Residual inflammation is evaluated by the reactive oxygen species activity. The true damage caused by inflammation on spermatozoa is reflected in negative changes observed during sperm apoptosis. Increased sperm DNA fragmentation is frequently observed while classical sperm characteristics are not modified automatically. The diagnosis of genital tract inflammation, follow-up after treatment and prognosis in terms of fertility require the use of different and complementary parameters.

Semen polymorphonuclear neutrophil leukocyte elastase as a diagnostic and prognostic marker of genital tract inflammation--a review.

Elastase is a protease released by polymorphonuclear neutrophils (PMN) during the inflammatory process. Since 1987, seminal elastase-inhibitor complex (Ela/alpha1-PI) has been proposed as a marker of male silent genital tract inflammation. Measured by immunoassay in seminal plasma, Ela/alpha1-PI at a cut-off level of > or = 230 microg/l, is useful in the detection of genital tract inflammation. The prevalence of increased seminal Ela/alpha1-PI in infertile men is significantly higher than that observed in fertile men. The Ela/alpha1-PI level is positively correlated with other seminal fluid markers of male genital tract inflammation: reduced semen volume, citric acid, fructose, and increased albumin, complement component C3, caeruloplasmin, immunoglobulins IgG and IgA, and cytokines interleukins-8 and -6. A higher seminal Ela/alpha1-PI level is significantly associated with tubal damage in female partners. After antibiotic therapy, a decrease of Ela/alpha1-PI level is observed. The presence of tubal damage in the partner may negatively affect the response to antibiotic treatment. A higher seminal Ela/alpha1-PI is associated with lower percentage of sperm with single-stranded deoxyribonucleic acid (DNA) and better fertilization rate in in vitro fertilization. Besides infertility, the determination of Ela/alpha1-PI is useful to confirm the presence of prostate and other male accessory gland bacterial inflammation. Screening for PMN Ela/alpha1-PI is easy to perform and reproducible and is a reliable quantitative test for diagnosis and prognosis of silent genital tract inflammation of couples. Moreover, sequential determinations allow the follow-up of inflammation during and after therapy.

Granulocyte elastase indicates silent male genital tract inflammation and appropriate anti-inflammatory treatment.

Diagnosis of male genital inflammations plays a significant role in andrology. Although genital infections are often silent, they can severely impair male fertility. In the seminal plasma of 305 patients, immunoglobulins IgG, IgA, complement factor C3C, coeruloplasmin and the number of peroxidase-positive cells were determined in addition to conventional semen parameters and microbiological investigations. A leukocyte esterase dipstick test was also carried out. All these parameters were correlated with the granulocyte elastase determined by an enzyme immunoassay. A highly significant correlation between elastase concentrations and the other parameters indicating inflammation was observed. After anti-inflammatory treatment, elastase concentrations decreased markedly. The results showed that exact quantification of granulocyte elastase is a very specific and sensitive method to distinguish inflammatory from non-inflammatory male adnexal affections, which is appropriate for control of anti-inflammatory treatment and facilitates the diagnosis of inflammatory processes in andrology.

Seminal alpha-glucosidase activity as a marker of epididymal pathology in nonazoospermic men consulting for infertility.

Glucosidase (alpha G) activity was measured in sperm free seminal plasma from 1200 patients consulting for primary infertility, in whom clinical examination of epididymides revealed some abnormalities and histories of genital infections. They constituted the group with epididymal pathology (P) that was compared with a reference group (R) of 246 men without any epididymal pathology. The distribution of alpha G was significantly different between the two groups, even if we considered only the subjects in group P with normal sperm count (PN: 353 men: p less than 10(-6). 15.9% of subjects in group PN exhibited alpha G values as low as vasectomized men, versus 1.2% in group R. A linear relationship was established between alpha G and sperm content in both groups, but alpha G activities were systematically lower in group P (y = 0.19 x + 64) than in group R (y = 0.30 x + 86). There was no correlation between alpha G and the percent of sperm motility. On the contrary, we found statistically more clinical epididymal abnormalities in cases of decreased alpha G activity than in cases of normal alpha G activity (p less than .01).

Elastase as an indicator of silent genital tract infection in infertile men.

Due to the absence of clinical symptoms, silent genital tract inflammation can be diagnosed only by laboratory tests. In this study we have evaluated seminal plasma elastase levels, using an immunoabsorbent assay, in a group of 84 infertile men. Seminal plasma levels of elastase were correlated with the number of white blood cells in the ejaculate, the number of peroxidase-positive leucocytes and with sperm culture. A high number of leucocytes (greater than 10) and a significantly higher number of men with peroxidase-stained leucocytes exceeding 10(6)/ml was found in a group of men with elastase levels greater than 250 ng/ml. There was a significant correlation between sperm culture results and elastase levels, most men with negative sperm culture having a lower seminal plasma elastase level. Following the treatment with antibiotics of men with an elevated elastase level, sperm parameters improved in 67% of those in whom elastase levels were lowered after treatment. In those men with persisting elevated levels of elastase improvement of sperm parameters was found in only 10%. It is concluded that an elevated level of elastase is a sensitive indicator of asymptomatic genital tract infection and that a single determination gives a reliable criterion and relatively exact quantification of infection.

Altered glycosylation of gamma-glutamyltranspeptidase (GGT) in seminal fluid from men with accessory gland infection.

The heterogeneity of gamma-glutamyltranspeptidase (GGT) in seminal plasma has been studied using Con A-chromatography. This parameter was then related to the fructose concentration, the acid phosphatase activity, ejaculate volume, sperm density and the number of bacteria per ml. Multivariate regression analysis and stepwise elimination of the least fitting factors, revealed that Con A-binding correlated with the number of bacteria per ml of semen and the acid phosphatase activity with 49% of the variance of GGT-binding being explained by these parameters. This result suggests that glycosylation of seminal GGT is altered by accessory gland infection. Neuraminidase digestion suggests that the pattern of Con A-binding of seminal GGT depends only partly on its sialic acid content.