Insulin-like growth factor I (IGF-I) and IGF binding proteins in seminal plasma before and after vasectomy in normal men

NGF, EPO, and IGF-1 in the Male Reproductive System

Several studies have demonstrated interesting results considering the implication of three growth factors (GFs), namely nerve growth factor (NGF), erythropoietin (EPO), and the insulin-like growth factor-I (IGF-1) in the physiology of male reproductive functions. This review provides insights into the effects of NGF, EPO, and IGF-1 on the male reproductive system, emphasizing mainly their effects on sperm motility and vitality. In the male reproductive system, the expression pattern of the NGF system varies according to the species and testicular development, playing a crucial role in morphogenesis and spermatogenesis. In humans, it seems that NGF positively affects sperm motility parameters and NGF supplementation in cryopreservation media improves post-thaw sperm motility. In animals, EPO is found in various male reproductive tissues, and in humans, the protein is present in seminal plasma and testicular germ cells. EPO receptors have been discovered in the plasma membrane of human spermatozoa, suggesting potential roles in sperm motility and vitality. In humans, IGF-1 is expressed mainly in Sertoli cells and is present in seminal plasma, contributing to cell development and the maturation of spermatozoa. IGF-1 seems to modulate sperm motility, and treatment with IGF-1 has a positive effect on sperm motility and vitality. Furthermore, lower levels of NGF or IGF-1 in seminal plasma are associated with infertility. Understanding the mechanisms of actions of these GFs in the male reproductive system may improve the outcome of sperm processing techniques.

Association of decreased sperm motility and increased seminal plasma IGF-I, IGF-II, IGFBP-2, and PSA levels in infertile men

PURPOSE

Previous studies have suggested the involvement of serum insulin-like growth factors (IGFs) and IGF binding proteins (IGFBPs) in the regulation of the female reproductive system. Little is known of these peptides in the seminal plasma (SP) of men and their potential effects on fertility. We assessed SP levels of these peptides in infertile men with low sperm motility (asthenozoospermic; AZ) and low sperm counts (oligozoospermic; OZ), its effects on in vivo sperm motility, and whether there is a correlation with aging.

METHODS

Twenty-eight infertile men (AZ; n = 18 and OZ; n = 10) and 20 fertile normozoospermic (NZ) men were studied. Seminal plasma IGF-I, IGF-II, IGFBP-2, IGFBP-3, and prostate-specific antigen (PSA) levels were measured, and spermatozoa mRNA transcript patterns were examined.

RESULTS

Asthenozoospermic men had higher SP IGF-I, IGF-II, IGFBP-2, and PSA levels than NZ and OZ men, whereas SP IGFBP-3 levels were similar between the three groups. Sperm count positively correlated with SP IGF-I, IGF-II, and IGFBP-2; sperm motility negatively correlated with SP IGF-II and IGFBP-2; and age correlated positively with SP IGF-II. The expression of IGF-I and IGF-II mRNA and mRNA receptors was detectable, but no variations in transcript levels were noted.

CONCLUSION

Decreased sperm motility, but not sperm count, in infertile AZ men is associated with increased SP IGF-I, IGF-II, IGFBP-2, and PSA levels. Changes in SP IGFs and their interactions with IGFBPs and IGF receptors, and PSA levels suggest a role of these SP peptides in modulating sperm motility and possibly prostate disease development in aging men.

Hypothetical Role of Growth Factors to Reduce Intervertebral Disc Degeneration Significantly through Trained Biological Transformations

BACKGROUND

Given the evidence of little or no therapeutic benefit of injection-based growth factor therapies, it has been proposed that a naturally triggered uninterrupted blood circulation of the growth factors would be superior.

OBJECTIVE

We seek to stimulate discussions and more research about the possibility of using the already available growth factors found in the prostate gland and endometrium by starting novel educable physiology, known as biological transformations controlled by the mind.

METHODS

We summarized the stretch-gated ion channel mechanism of the cell membrane and offer several practical methods that can be applied by anyone, in order to stimulate and enhance the blood circulation of the growth factors from the seminal fluid to sites throughout the body. This study describes, in detail, the practical application of our earlier published studies about biological transformations.

RESULTS

A previously reported single-patient case study has been extended, adding more from his personal experiences to continually improve this novel physiological training and extending the ideas from our earlier findings in detail.

CONCLUSION

The biological transformation findings demonstrate the need for additional research to establish the benefits of these natural therapies to repair and rejuvenate tissues affected by various chronic diseases or aging processes.

Impact of Vasectomy on the Development and Progression of Prostate Cancer: Preclinical Evidence

Some observational studies have implied a link between vasectomy and an elevated risk of prostate cancer. We investigated the impact of vasectomy on prostate cancer outgrowth, mainly using preclinical models. Neoplastic changes in the prostate were compared in transgenic TRAMP mice that underwent vasectomy vs. sham surgery performed at 4 weeks of age. One of the molecules identified by DNA microarray (i.e., ZKSCAN3) was then assessed in radical prostatectomy specimens and human prostate cancer lines. At 24 weeks, gross tumor (p = 0.089) and poorly differentiated adenocarcinoma (p = 0.036) occurred more often in vasectomized mice. Vasectomy significantly induced ZKSCAN3 expression in prostate tissues from C57BL/6 mice and prostate cancers from TRAMP mice. Immunohistochemistry showed increased ZKSCAN3 expression in adenocarcinoma vs. prostatic intraepithelial neoplasia (PIN), PIN vs. non-neoplastic prostate, Grade Group ≥3 vs. ≤2 tumors, pT3 vs. pT2 tumors, pN1 vs. pN0 tumors, and prostate cancer from patients with a history of vasectomy. Additionally, strong (2+/3+) ZKSCAN3 expression (p = 0.002), as an independent prognosticator, or vasectomy (p = 0.072) was associated with the risk of tumor recurrence. In prostate cancer lines, ZKSCAN3 silencing resulted in significant decreases in cell proliferation/migration/invasion. These findings suggest that there might be an association between vasectomy and the development and progression of prostate cancer, with up-regulation of ZKSCAN3 expression as a potential underlying mechanism.

Serum and seminal plasma insulin-like growth factor-1 in male infertility

OBJECTIVE

Growth hormone and its mediator, insulin-like growth factor-1 (IGF-1), have been suggested to exert gonadotropic actions in both humans and animals. The present study was conducted to assess the relationship between serum IGF-1 concentration, seminal plasma concentration, and sperm parameter abnormalities.

METHODS

A total of 79 men were enrolled in this study from December 2011 to July 2012 and were prospectively analyzed. Patient parameters analyzed included age, body mass index, smoking status, urological history, and fertility history. Patients were divided into four groups based on their semen parameters: normal (A, n=31), abnormal sperm motility (B, n=12), abnormal sperm morphology (C, n=20), and two or more abnormal parameters (D, n=16). Patient seminal plasma and serum IGF-1 concentrations were determined.

RESULTS

Patient baseline characteristics were not significantly different between any of the groups. The serum IGF-1 levels in groups B, C, and D were significantly lower than the levels in group A; however, the seminal plasma IGF-1 levels were not significantly different between any of the groups.

CONCLUSION

Men with abnormal sperm parameters had significantly lower levels of serum IGF-1 compared with men with normal sperm parameters. Seminal plasma IGF-1 levels, however, did not differ significantly between the groups investigated here. Further investigations will be required to determine the exact mechanisms by which growth hormone and IGF-1 affect sperm quality.

Vasectomy: potential links to an increased risk of aggressive prostate cancer?

Several studies have found associations between aggressive prostate cancer (PC) and having a vasectomy. However, findings from two very recent meta-analyses have found that this is not the case. Therefore, the data are mixed. Herein, we detail the controversy between vasectomy and PC risk, particularly aggressive PC, by shedding some light on the molecular pathways, potential risk factors and suggested links for those considering vasectomy and medical professionals who perform it. We conclude by supporting the American Urological Association's position that there is no need to discuss potential prostate cancer risks with patients considering vasectomy given reasonably strong data finding no link between vasectomy and prostate cancer risk.

Oral clonidine advances spermatogenesis in oligozoospermic patients with spermatogenetic maturation arrest

BACKGROUND

Growth hormone (GH) plays an important role in the pubertal development of males and females, and influences the male reproductive function after puberty. The purpose of this study was to investigate the cause of GH deficiency in infertile men with spermatogenetic maturation arrest using the clonidine loading test (GH stimulation test). Based on the results of the loading test, we tried to con fi rm whether clonidine might be usable as a male infertility remedy.

METHODS

We studied 75 infertile men (55 oligozoospermic and 20 azoospermic men) and 25 normal fertile volunteers. We used the oral clonidine (0.15 mg/m2) loading test to evaluate the GH secretory reserve. Histological diagnoses were performed using testicular biopsy and testicular sperm extraction specimens.

RESULTS

The most important finding was that the clonidine loading test caused a good response in 41 out of 55 (74.6%) patients with oligozoospermia. We treated these 41 good-response patients with oral clonidine, and the sperm count improved in 34 (82.9%) cases, increasing to 12-79 million/mL. Spontaneous pregnancy was subsequently achieved by 10 (24.4%) couples.

CONCLUSIONS

These findings also suggest that GH is necessary for spermatogenesis, at least for the process of spermatozoa maturation. Oral clonidine therapy improved the sperm count in patients who showed an excessive response to the clonidine loading test.

Insulin-like growth factor-I and insulin-like growth factor binding protein-2 and -5 in equine seminal plasma: association with sperm characteristics and fertility

The objectives of this study were 1) to determine whether insulin-like growth factor-I (IGF-I) and insulin-like growth factor binding proteins (IGFBPs) were present in seminal plasma of stallions; 2) to compare semen parameters (IGF proteins, sperm numbers, morphology, and motility) from stallions at sexual rest (SR) and when sexually active (SA); 3) to compare semen parameters between stallions with high and low seminal plasma IGF-I concentrations; and 4) to examine the relationship between seminal plasma IGF-I concentrations and fertility parameters of stallions. Ejaculates were collected from stallions at SR (n = 51) and SA (n = 46). Concentrations of IGF-I and IGFBP-2 in seminal plasma samples were determined by radioimmunoassay. Presence of IGFBPs in equine seminal plasma was verified using immunoprecipitation and Western ligand blot procedures. IGF-I, IGFBP-2, and IGFBP-5 were present in equine seminal plasma. Concentrations of IGF-I, IGF-I/protein, total IGF-I, IGFBP-2, IGFBP-2/protein, and total IGFBP-2 were not significantly different (P > or = 0.13) in seminal plasma between stallions at either SR or SA. At SR, stallions with higher seminal plasma IGF-I had more total IGFBP-2 per ejaculate (P < 0.01), more morphologically normal sperm (P = 0.05), and higher first-cycle pregnancy rates (P = 0.02). At SA, stallions with higher seminal plasma IGF-I had fewer cycles per pregnancy (P = 0.02). An association of seminal plasma IGF-I concentration with sperm motility, sperm morphology, and pregnancy rates in bred mares suggests that IGF-I may play a role in sperm function.

Identification of insulin-like growth factor (IGF)-1 receptor in human sperm cell

The present study was conducted to examine the presence of insulin-like growth factor- receptor (IGF-1R) in human sperm cell. The IGF-1R monoclonal antibody (MAb) specifically immunoprecipitated two protein bands of approximately 135 and approximately 220 kD, respectively, from the reduced human sperm extract. These bands correspond to the alpha-subunit and partially reduced IGF-1R molecule, respectively. The immunocytochemistry experiments indicated the presence of IGF-1R primarily in the equatorial regions, along with a weak binding in the acrosomal regions of human spermatozoa. These data indicate that the IGF-1 receptor is present in the human sperm cell. Since the IGF-1 receptor has tyrosine kinase activity and its ligand IGF-1 is present in the seminal plasma, the IGF-1 system (IGF-1R/IGF-1/IGF-binding protein) may be involved in the signal transduction pathway leading to sperm capacitation and acrosome exocytosis.

IGF-I treatment increases motility and improves morphology of immature spermatozoa in the GH-deficient dwarf (dw/dw) rat

It has recently been shown that short-term growth hormone (GH) treatment can increase the motility of spermatozoa in the GH-deficient dw/dw rat. To examine whether the effects of GH on motility of immature spermatozoa are mediated by an increase in plasma concentrations of IGF-I, we treated GH-deficient dw/dw rats with 2 microg/g/day of IGF-I using osmotic minipumps. Body weight (saline 227+/-5 g, IGF-I 253+/-4 g) and IGF-I concentrations in blood plasma (saline 472+/-19.9 ng/ml, IGF-I 986+/-43.6 ng/ml) and seminal vesicle fluid (saline 30.9+/-1.7 ng/ml, IGF-I 47.9+/-2.9 ng/ml) were significantly increased with IGF-I treatment (P<0.001), similar to the observed responses to GH therapy in our earlier study. While epididymal fluid IGF-I concentrations were not changed, IGF-I treatment significantly increased the number of immature motile spermatozoa (saline 14.4+/-3.5%, IGF-I 28.3+/-4.1%, P<0.05) and the number of spermatozoa with normal morphology (control 65.7+/-3.3%, IGF-I 75+/-1.9%, P<0.05). These data suggest that increasing the circulating concentrations of IGF-I in the GH-deficient rat can improve the motility and morphology of immature spermatozoa and thus mimic, at least in part, the effects of GH.

Insulin-like growth factors and IGF-binding proteins in bovine seminal plasma

Insulin-like growth factor-I (IGF-I) is an important factor for germ cell development and maturation of spermatozoa. Actions of IGFs are modulated by IGF-binding proteins (IGFBPs) that may, depending on their concentration and site of expression, inhibit or enhance effects of IGF-I. We characterized IGFs and IGFBPs in seminal plasma from bulls routinely used for artificial insemination (AI) and from bulls producing poor-quality semen (low mass and individual motility of spermatozoa). IGFs were measured by specific radioimmunoassay in 22 samples of seminal plasma from nine different AI bulls with high (> 76.8%), average (72.8-73.4%), or low (< 69.5%) nonreturn rate (NRR). IGF-I and IGF-II levels were 144 +/- 9 ng/ml (mean +/- SE; range, 79-238 ng/ml) and 144 +/- 10 ng/ml (range, 55-221 ng/ml), respectively, and did not correlate with NRRs. IGF-I concentrations in seminal plasma from bulls producing poor-quality semen (n = 10) were significantly (P < 0.05) greater (194 +/- 26 ng/ml; range, 94-370 ng/ml), whereas IGF-II levels were significantly (P < 0.05) lower (93 +/- 17 ng/ml; range, 38-183 ng/ml) than in AI bulls. Ligand blot analysis of seminal plasma for IGFBPs revealed the presence of a 38-/45-kDa doublet band and a 30-kDa IGFBP. These IGFBPs were identified as IGFBP-3 and IGFBP-5, respectively, by immunoprecipitation using specific antibodies. In addition, a low amount of IGFBP-4 was detected in bovine seminal plasma by immunoprecipitation. There was a marked difference in the activity of IGFBPs between individual bulls, with a relatively small within-bull variance. The differences in IGFBP activities did not correlate with the fertilization capacity of the bulls in vivo or in vitro nor with immunoreactive IGF-I and IGF-II levels in seminal plasma. Our results demonstrate the presence of IGFBPs in bovine seminal plasma. In contrast to human seminal plasma, high activity of IGFBP-3 was detected in seminal plasma of some bulls, suggesting species-specific regulation of IGFBP activity by proteases.

Similarities between the uterine decidual reaction and the "mesenchymal lesion" of the urinary bladder in aging mice

The histopathologic characteristics of the decidual reaction in the uterus of aging mice and the "mesenchymal lesion/tumor" in the urinary bladder of aging mice are compared and found to be very similar. Both lesions consist of spindle and epithelioid cells, may contain round eosinophilic granules and possess nuclear progesterone receptors and cytoplasmic desmin. The decidual reaction derives from endometrial stromal cells, while the "mesenchymal lesion" apparently develops from mesenchymal cells near the trigone area, carrying or developing progesterone receptors. If the hypothesis is accepted that in aging mice the uterine decidual reaction and the "mesenchymal lesion" in the urinary bladder represent an equivalent type of tissue reaction, then it follows that the typical "mesenchymal lesion" is not a tumor and could be called more specifically "decidual-like reaction".

Growth hormone treatment of subfertile males

OBJECTIVE

To study spermatogenesis and sperm motility during GH therapy in infertile men.

DESIGN

Prospective open study. Each patient was treated with GH for 12 weeks and followed for a total of 36 weeks with sampling of blood and semen.

SETTING

Outpatients studied at a clinical research unit of a university hospital.

PATIENTS

Nine oligozoospermic (<5 x 10(6) sperm/mL) males and nine asthenozoospermic (percentage motile sperm <30 and >15 x 10(6) sperm/mL) males. The patient groups had a significantly lower GH response to an arginine GH stimulation test as compared with a control group.

RESULTS

Serum insulin-like growth factor I (IGF-I) and serum IGF-binding protein 3 (IGFBP-3) levels increased significantly during GH treatment, as did seminal IGF-I. Serum E2, T, PRL, FSH, LH, and GH-binding protein were unchanged during the study. Sperm motility was increased significantly during GH treatment in both patient groups. There was no difference in sperm count during the treatment. There were three pregnancies in the nine couples from the asthenozoospermic group and no pregnancies in the oligozoospermic group.

CONCLUSION

The biologic and clinical results in this study encourage the initiation of double-blind, placebo-controlled trials.

Effect of growth hormone cotreatment with human chorionic gonadotropin in testicular steroidogenesis and seminal insulin-like growth factor-1 in oligozoospermia

OBJECTIVE

To study the GH synergy with hCG in testicular steroidogenesis and seminal insulin-like growth factor-1 (IGF-1) in oligozoospermia.

SETTING

University endocrine unit.

PATIENTS

Eight oligospermic, non-GH-deficient men.

INTERVENTIONS

Three different protocols spaced 3 months apart were applied in each man: plain hCG protocol: 1,500 IU IM three times every other day; GH + hCG protocol: with the addition of 4 IU SC GH daily 8 days before and throughout the hCG phase; placebo + hCG: substitution of GH by NaCL 0.9%. Blood sampling was performed before and on the 8th day (for 2nd- and 3rd-day protocols) and 24 hours after each hCG administration. Semen was collected three times during each protocol.

MAIN OUTCOME MEASURES

Plasma for P, 17-OHP, androstenedione, DHEA, DHEAS, T, and E2 and plasma and seminal IGF-1 three times during each study.

RESULTS

Serum IGF-1 levels increased more than threefold after GH administration. Seminal IGF-1 activity was unaffected by GH treatment or hCG administration, showing random fluctuations within each subject without correlation to the respective plasma levels. The incremental response of each steroid under hCG did not differ between the three protocols, apart from increased P levels under GH.

CONCLUSIONS

Short-term GH cotreatment with hCG did not affect seminal IGF-1 concentration and had a weak synergist effect on steroidogenesis.