Late onset hypogonadism, sexuality and fertility

Hypothalamic Response to Kisspeptin-54 and Pituitary Response to Gonadotropin-Releasing Hormone Are Preserved in Healthy Older Men

BACKGROUND

Male testosterone levels decline by 1% per year from the age of 40 years. Whilst a primary testicular deficit occurs, hypothalamic or pituitary dysregulation may also coexist. This study aimed to compare the hypothalamic response to kisspeptin-54 and the pituitary response to gonadotropin-releasing hormone (GnRH) of older men with those of young men.

METHODS

Following 1 h of baseline sampling, healthy older men (n = 5, mean age 59.3 ± 2.9 years) received a 3-h intravenous infusion of either vehicle, kisspeptin-54 0.1, 0.3, or 1.0 nmol/kg/h or GnRH 0.1 nmol/kg/h, on five different study days. Serum gonadotropins and total testosterone were measured every 10 min and compared to those of young men (n = 5/group) (mean age 28.9 ± 2.0 years) with a similar body mass index (24 kg/m2) who underwent the same protocol.

RESULTS

Kisspeptin-54 and GnRH significantly stimulated serum gonadotropin release in older men compared to vehicle (p < 0.001 for all groups). Gonadotropin response to kisspeptin-54 was at least preserved in older men when compared to young men. At the highest dose of kisspeptin-54 (1.0 nmol/kg/h), a significantly greater luteinising hormone (LH) (p = 0.003) response was observed in older men. The follicle-stimulating hormone (FSH) response to GnRH was increased in older men (p = 0.002), but the LH response was similar (p = 0.38). Serum testosterone rises following all doses of kisspeptin-54 (p ≤ 0.009) were reduced in older men.

CONCLUSIONS

Our data suggest that healthy older men without late-onset hypo-gonadism (LOH) have preserved hypothalamic response to kisspeptin-54 and pituitary response to GnRH, but impaired testicular response. Further work is required to investigate the use of kisspeptin-54 to identify hypothalamic deficits in men with LOH.

The relationship between lipoprotein-associated phospholipase A2 with cardiovascular risk factors in testosterone deficiency

Objective

Lipoprotein-associated phospholipase A2 (Lp-PLA2) which is believed to play a role in atherosclerotic inflammatory process due to its function in hydrolysis of phospholipids and release of pro-inflammatory products, is considered as a novel biomarker for vascular risk. In this study we aimed to investigate the alterations in Lp-PLA2 and its relationship with other cardiovascular risk factors in patients with testosterone deficiency.

Material and methods

Forty hypogonadic male and 30 healthy male aged between 18-50 years were enrolled in this study. Height-weight, waist-to-hip circumference, body mass index (BMI) blood pressure, and body fat measurements were performed in all subjects. Blood glucose, albumin, total cholesterol, HDL-cholesterol, LDL-cholesterol, triglycerides, high sensitive C-reactive protein (hs-CRP), apo-A1, apo-B, fibrinogen, insulin, total testosterone, sex hormone binding globulin (SHBG), small dense low-density lipoprotein (sd-LDL), paraoxonase 1, oxidized low-density lipoprotein (ox-LDL) and Lp-PLA 2 values were measured. Free and bioavailable testosterone levels were calculated. Data management was carried out with the statistical program SAS Version 9.2. Statistical evaluations were performed using Analysis of Variance (ANOVA), Kruskal-Wallis test, Wilcoxon test, correlation analysis and chi-square analysis. P values <0.05 were considered statistically significant.

Results

In patients with hypogonadism, significant increase in Lp-PLA2 levels were accompanied with risk factors of atherosclerosis, such as increase in total cholesterol, apo-B, sd-LDL, weight, BMI, body fat percentage, and decrease in paraoxonase 1 levels. Although the differences were not significant, similarly ox-LDL, hs-CRP, triglyceride, LDL-cholesterol levels were found to be higher in patients with hypogonadism compared to the control group. The mean level of Lp-PLA2 was the highest when compared with the group of secondary hypogonadism with the lowest testosterone level.

Conlusion

Our study has demonstrated that the testosterone deficiency increases cardiovascular risk via its effects on lipid metabolism and Lp-PLA2 can be used to assess this risk.

Effects of Saikokaryukotsuboreito on Spermatogenesis and Fertility in Aging Male Mice

Background:

Aspermia caused by exogenous testosterone limit its usage in late-onset hypogonadism (LOH) patients desiring fertility. Saikokaryukotsuboreito (SKRBT) is reported to improve serum testosterone and relieve LOH-related symptoms. However, it is unclear whether SKRBT affects fertility. We aimed to examine the effects of SKRBT on spermatogenesis and fertility in aging male mice.

Methods:

Thirty aging male mice were randomly assigned to three groups. Mice were orally administered with phosphate-buffer solution or SKRBT (300 mg/kg, daily) or received testosterone by subcutaneous injections (10 mg/kg, every 3 days). Thirty days later, each male mouse was mated with two female mice. All animals were sacrificed at the end of 90 days. Intratesticular testosterone (ITT) levels, quality of sperm, expression of synaptonemal complex protein 3 (SYCP3), and fertility were assayed.

Results:

In the SKRBT-treated group, ITT, quality of sperm, and expression of SYCP3 were all improved compared with the control group (ITT: 85.50 ± 12.31 ng/g vs. 74.10 ± 11.45 ng/g, P = 0.027; sperm number: [14.94 ± 4.63] × 10⁶ cells/ml vs. [8.79 ± 4.38] × 10⁶ cells/ml, P = 0.002; sperm motility: 43.16 ± 9.93% vs. 33.51 ± 6.98%, P = 0.015; the number of SYCP3-positive cells/tubule: 77.50 ± 11.01 ng/ml vs. 49.30 ± 8.73 ng/ml, P < 0.001; the expression of SYCP3 protein: 1.23 ± 0.09 vs. 0.84 ± 0.10, P < 0.001), but fertility was not significantly changed (P > 0.05, respectively). In the testosterone-treated group, ITT, quality of sperm, and expression of SYCP3 were markedly lower than the control group (ITT: 59.00 ± 8.67, P = 0.005; sperm number: [4.34 ± 2.45] × 10⁶ cells/ml, P = 0.018; sperm motility: 19.53 ± 7.69%, P = 0.001; the number of SYCP3-positive cells/tubule: 30.00 ± 11.28, P < 0.001; the percentage of SYCP3-positive tubules/section 71.98 ± 8.88%, P = 0.001; the expression of SYCP3 protein: 0.71 ± 0.09, P < 0.001), and fertility was also suppressed (P < 0.05, respectively).

Conclusion:

SKRBT had no adverse effect on fertility potential in aging male mice.

Role of peroxiredoxin 2 in H2O2‑induced oxidative stress of primary Leydig cells

Late‑onset hypogonadism is defined as a condition caused by a decline in the levels of testosterone with aging. One of the major factors contributing to the low levels of testosterone is the accumulation of reactive oxygen species (ROS) in Leydig cells during the ageing process. Peroxiredoxin 2 (Prdx2), a member of the peroxiredoxin family, is an antioxidant protein, the predominant function of which is to neutralize ROS. However, its role in Leydig cells remains to be elucidated. In the present study, primary Leydig cells were exposed to low concentrations of hydrogen peroxide (H2O2) to induce oxidative stress. Cell apoptosis was measured using an Annexin V fluorescein isothiocyanate/propidium iodide apoptosis detection kit and flow cytometry. The level of testosterone was determined by radioimmunoassay, and the mRNA and protein expression levels of Prdx2 were detected by reverse transcription‑polymerase chain reaction and western blotting, respectively. The results revealed a significant increase in cell apoptosis and decrease in testosterone production. In addition, the expression of Prdx2 was decreased by H2O2 in a dose‑ and time‑dependent manner, and this decrease may have been caused by the induction of its molecular structure transformation due to H2O2 elimination. The above findings indicated that Prdx2 may prevent H2O2 accumulation in Leydig cells, and may be important in oxidative stress‑induced apoptosis and decreased testosterone production.

Andropause - state of the art 2015 and review of selected aspects

The term ‘male menopause’ was first used in 1944 to describe various complaints of ageing men which at least partially mirrored the climacteric symptoms in women. Continuous research resulted in the evolution of opinions about the nature of these complaints, from the clinical syndrome, diagnosed with the use of disease-targeted questionnaires, to a well-defined clinical and biochemical syndrome. The pathophysiological causes – gonad ageing (with a compensatory rise in luteinizing hormone), age-related increase in serum sex hormone-binding globulin (SHBG) levels, the role of visceral adipose tissue as a place for aromatization of androgen to estrogen, and lower sensitivity of testosterone receptors – have been described. However, no consensus was reached as far as the definition, incidence, treatment, and especially testosterone therapy, are concerned. Our review presents the current standpoints, indicating the predictive role of late-onset hypogonadism (LOH) in evaluating male health as well as the current literature reports on the risks and benefits of using testosterone therapy.

Hypogonadism in the aging male diagnosis, potential benefits, and risks of testosterone replacement therapy

Hypogonadism in older men is a syndrome characterized by low serum testosterone levels and clinical symptoms often seen in hypogonadal men of younger age. These symptoms include decreased libido, erectile dysfunction, decreased vitality, decreased muscle mass, increased adiposity, depressed mood, osteopenia, and osteoporosis. Hypogonadism is a common disorder in aging men with a significant percentage of men over 60 years of age having serum testosterone levels below the lower limits of young male adults. There are a variety of testosterone formulations available for treatment of hypogonadism. Data from many small studies indicate that testosterone therapy offers several potential benefits to older hypogonadal men. A large multicenter NIH supported double blind, placebo controlled study is ongoing, and this study should greatly enhance the information available on efficacy and side effects of treatment. While safety data is available across many age groups, there are still unresolved concerns associated with testosterone therapy. We have reviewed the diagnostic methods as well as benefits and risks of testosterone replacement therapy for hypogonadism in aging men.

Survey for late-onset hypogonadism among old and middle-aged males in Shanghai communities

This study sought to investigate late-onset hypogonadism (LOH) in old and middle-aged males in Shanghai communities, using symptom score evaluation systems and measurements of sex hormone levels. One thousand cases of males aged 40-70 years were investigated. The aging male symptoms (AMS) scale and androgen deficiency in aging males (ADAM) questionnaire were used at the beginning of the investigation, followed by measurement of the sex hormone-related factors (total testosterone (TT), free testosterone (fT), sex hormone-binding globulin (SHBG) and bioavailability of testosterone (Bio-T)). There were 977 valid questionnaires. The LOH-positive rates shown by AMS and ADAM were 59.88% and 84.65%, respectively; values increased with the age of the patients. There were 946 results related to sex hormone measurements, which showed the following results: TT was not related to aging (P>0.05); levels of SHBG increased with age; and fT and Bio-T decreased with age. There was a significant difference in fT between LOH-positive and LOH-negative patients, as shown by the ADAM. In summary, TT levels were not related to aging, even though SHBG did increase while fT and Bio-T decreased with aging. Clinically, the diagnosis of LOH cannot be based on serum TT level.