Impact of Bariatric Surgery on Sexual Dysfunction in Obese Men

Weight Loss as Therapeutic Option to Restore Fertility in Obese Men: A Meta-Analytic Study

PURPOSE

Weight loss has been shown to significantly elevate testosterone serum levels, though the impact on semen analysis parameters and fertility remains incompletely understood. The objective of this study was to examine the influence of body weight loss on semen parameters in obese men.

MATERIALS AND METHODS

A meta-analysis was performed that included clinical trials in which a semen analysis before and after weight loss was evaluated. All strategies potentially available for weight loss were considered eligible. The primary outcome was the comparison of conventional semen analysis parameters before and after weight loss.

RESULTS

Twelve studies were considered including 345 subjects (mean age 37.6±7.9 years; mean baseline body mass index 45.4±6.0 kg/m²). Weight loss resulted in a significant increase of sperm concentration (effect size 0.495, standard error 0.251 [0.003, 0.986], p=0.049) and progressive motility (effect size 0.567, standard error 0.372 [0.370, 0.764], p<0.001). Moreover, a significant decrease of sperm DNA fragmentation index after weight loss (effect size -0.689, standard error 0.278 [-1.123, -0.255], p=0.002) was observed.

CONCLUSIONS

This meta-analytic analysis confirmed that body weight loss may improve qualitative and quantitative sperm characteristics providing evidence for suggesting weight loss to male partners with obesity and semen analysis alteration in couples attempting conception.

Erectile Dysfunction Therapy of Bariatric Patients: Tadalafil Biopharmaceutics and Pharmacokinetics Before vs. After Gastric Sleeve/Bypass

Bariatric surgery introduces significant changes in the gastrointestinal tract, which may affect oral drug absorption/bioavailability. Here we investigate the phosphodiesterase-5 inhibitor (PDE5i) tadalafil for potentially impaired post-bariatric solubility/dissolution and absorption. Solubility was studied in vitro in different pHs, and ex vivo in gastric content aspirated from patients pre/post-surgery. Dissolution was studied in conditions mimicking pre/post-surgery stomach. Finally, the experimental data were used in physiologically-based pharmacokinetic (PBPK) model (GastroPlus®) to simulate pre- vs. post-surgery tadalafil PK. Tadalafil demonstrated low and pH-independent solubility, both in vitro and ex vivo. Tadalafil release from all drug products and under all gastric conditions was incomplete, with particularly poor dissolution (2%) of the highest dose under post-bariatric conditions. PBPK simulations revealed altered tadalafil PK after gastric bypass-but not after sleeve gastrectomy-compared to unoperated individuals, with 44-48% decreased Cmax, 35-56% decreased AUC and 44% shorter Tmax. This mechanistic analysis suggests that tadalafil may be as effective after sleeve gastrectomy as before the procedure; meanwhile, results after gastric bypass raise concerns regarding the bioperformance of the drug. In addition, the drug's duration of action may be much shorter after gastric bypass. Thus, the effectiveness of tadalafil, widely regarded as the 'weekend pill', may be shorter than expected among gastric bypass patients.

Sexual and Urinary Health among Women following Bariatric Surgery

PURPOSE

Women with obesity are more likely to experience bothersome urinary and sexual symptoms, but the long-term effect of metabolic and bariatric surgery (MBS) on these outcomes is poorly understood. We aimed to describe how MBS longitudinally impacted women's urinary and sexual health.

METHODS

Patients who underwent MBS at the University of California, San Francisco Medical Center (UCSF) between 2009 and 2021 participated in a survey examining sexual health, pelvic organ prolapse (POP), and urinary health using three validated questionnaires: a modified version of the Female Sexual Function Index (FSFI), the Pelvic Organ Prolapse Distress Inventory 6 (POPDI-6), and the Urinary Distress Inventory 6 (UDI-6). All questions asked referenced two time points: before surgery and at the time of survey. Logistic regression identified predictors of symptom improvement.

RESULTS

Of 162 participants contacted, 118 (73%) had complete survey data. Mean body mass index (BMI) decreased from 52.4 ± 12.6 to 36.3 ± 9.7 kg/m2 (p < 0.01) with an average follow-up of 6 years. The mean UDI-6 score amongst women was 24 ± 24 prior to MBS and 24 ± 26 at the time of survey administration (p = 0.458). Mean modified FSFI scores amongst women were 15 ± 5 prior to surgery and 14 ± 7 at the time of survey administration (p = 0.005). The overall mean POPDI-6 score amongst women was 13 ± 15 prior to surgery and 9 ± 14 at the time of survey administration (p = 0.056).

CONCLUSION

Women who underwent MBS reported a high rate of sexual and urological dysfunction that did not improve longitudinally, despite significant weight loss.

Study on serum metabolomics characteristics of obese patients with erectile dysfunction

Erectile dysfunction (ED) is a common male sexual health problem that can be associated with obesity. This study aimed to identify serum metabolic differences and pathways related to ED in obese men using non-targeted metabolomics techniques. We included 54 obese male patients with (n = 27) and without (n = 27) ED. We collected 5 mL of fasting elbow vein blood and analyzed serum metabolites using ultra-high-performance liquid chromatography-mass spectrometry. Multivariate statistical methods (principal component analysis and orthogonal partial least squares discriminant analysis) were used to identify differential metabolites between the groups. Finally, pathway analysis using the Kyoto encyclopedia of genes and genomes database identified 4 differential metabolic pathways in obese men with ED compared to obese men without ED. A total of 77 differential metabolites were identified in obese men with ED compared to the control group (obese men without ED) using a threshold of variable importance in the projection > 1 and P < .05. Pathway analysis revealed 4 main differences: glycine, serine and threonine metabolism, glycerophospholipid metabolism, aminoacyl-tRNA biosynthesis, and D-glutamine and D-glutamate metabolism. Specific metabolites associated with these pathways included betaine aldehyde, choline, L-threonine, phosphatidylcholine, L-serine, and D-glutamine. Our findings suggest abnormalities in fatty acid metabolism, phospholipid metabolism, and amino acid metabolism between obese men with and without ED. Metabolites such as betaine aldehyde, choline, L-threonine, phosphatidylcholine, L-serine, and D-glutamine may be potential biomarkers for distinguishing obese men with ED.

ROUX-en-Y gastric bypass surgery improves metabolic syndrome-related erectile dysfunction in mice via the IRS-1/PI3K/AKT/eNOS pathway

Objective

Although many clinical studies have shown that ROUX-en-Y gastric bypass (RYGB) surgery significantly improves metabolic syndrome-related erectile dysfunction (MED), the role and mechanism are unclear.

Aim

In this study we used a mouse model to explore how RYGB improves MED induced by a high-fat diet (HFD).

Methods

We established a mouse model of metabolic syndrome by feeding an HFD for 16 weeks. The mice were randomly assigned to the standard chow diet (SCD), HFD, or RYGB groups. Body weight, fasting blood glucose, plasma insulin, and total plasma cholesterol were analyzed. Erectile responses were evaluated by determining the mean systolic blood pressure and the intracavernosal pressure (ICP). Penile histologic examination (Masson's trichrome and immunohistochemical stain) and Western blot were performed.

Result

Compared with the SCD group, the ICP in the sham group was significantly lower, and the ICP of the RYGB was significantly increased. Masson's trichrome and immunohistochemical staining showed that the content of endothelium and smooth muscle in the corpus cavernosum of mice with MED was significantly reduced. Western blot analysis showed a significant decrease in α-smooth muscle actin and a significant increase in osteopontin in penile tissue in the sham group, which was improved by RYGB surgery. Furthermore, RYGB significantly increased IRS-1/PI3K/Akt/eNOS phosphorylation.

Clinical Translation

In this study we explored the mechanism of bariatric surgery to improve erectile dysfunction associated with metabolic syndrome and provided a theoretical basis for clinical research.

Strengths and Limitations

First, we did not investigate the mechanism by which RYGB affects the IRS-1/PI3K/Akt/eNOS signaling pathway. Second, the effect of the IRS-1/PI3K/Akt/eNOS signaling pathway on the function of corpus cavernosum endothelial cells and smooth muscle cells remains to be investigated in cellular studies.

Conclusion

This study demonstrated that RYGB may not only improve metabolic parameters but also restore erectile function in MED patients. The mechanism of the therapeutic effect of RYGB may be reactivation of the IRS-1/PI3K/Akt/eNOS pathway.

The Complexity of Bariatric Patient's Pharmacotherapy: Sildenafil Biopharmaceutics and Pharmacokinetics before vs. after Gastric Sleeve/Bypass

Postbariatric altered gastrointestinal (GI) anatomy/physiology may significantly harm oral drug absorption and overall bioavailability. In this work, sildenafil, the first phosphodiesterase-5 (PDE5) inhibitor, was investigated for impaired postbariatric solubility/dissolution and absorption; this research question is of particular relevance since erectile dysfunction (ED) is associated with higher body mass index (BMI). Sildenafil solubility was determined both in vitro and ex vivo, using pre- vs. postsurgery gastric contents aspirated from patients. Dissolution tests were done in conditions mimicking the stomach before surgery, after sleeve gastrectomy (post-SG, pH 5), and after one anastomosis gastric bypass (post-OAGB, pH 7). Finally, these data were included in physiologically based pharmacokinetic (PBPK) modelling (GastroPlus®) to simulate sildenafil PK before vs. after surgery. pH-dependent solubility was demonstrated with low solubility (0.3 mg/mL) at pH 7 vs. high solubility at pH 1-5, which was also confirmed ex vivo with much lower solubility values in postbariatric gastric samples. Hampered dissolution of all sildenafil doses was obtained under post-OAGB conditions compared with complete (100%) dissolution under both presurgery and post-SG conditions. PBPK simulations revealed delayed sildenafil absorption in postbariatric patients (increased tmax) and reduced Cmax, especially in post-OAGB patients, relative to a presurgery state. Hence, the effect of bariatric surgery on sildenafil PK is unpredictable and may depend on the specific bariatric procedure. This mechanistically based analysis suggests a potentially undesirable delayed onset of action of sildenafil following gastric bypass surgery.

New perspectives in functional hypogonadotropic hypogonadism: beyond late onset hypogonadism

Functional hypogonadotropic hypogonadism (FHH) is an increasingly frequent condition, whose pathological mechanisms are not yet fully clarified. The concept of FHH has now completely replaced that of late onset hypogonadism, that only concerned the ageing man. FHH is the result of an impairment of the hypothalamic-pituitary gonadal axis (HPG-A) function, resulting in decreased testosterone concentrations associated with low or inappropriately normal gonadotropin levels and infertility; it can be diagnosed once organic causes of hypogonadism are excluded. The growing occurrence of FHH derives from its association with widespread conditions, such as obesity and diabetes mellitus, but also to the increasing ease and frequency of use of several drugs, such as opioids, glucocorticoids, and sex steroids. Moreover, given the tendency of many subjects to excessive physical activity and drastic reduction in caloric intake, FHH may also be secondary to low energy availability. Finally, the association with HIV infection should not be overlooked. Therefore, there is an important variability in the diseases that can lead to FHH. Despite the heterogeneity of the underlying pathologies, the mechanisms leading to FHH would seem quite similar, with the initial event represented by the impairment at the HPG-A level. Nevertheless, many different biological pathways are involved in the pathogenesis of FHH, therefore the aim of the current paper is to provide an overview of the main relevant mechanisms, through a detailed analysis of the literature, focusing specifically on pathogenesis and clinical, diagnostic and therapeutic aspects.

Influence of Bariatric Surgery on Erectile Dysfunction-a Systematic Review and Meta-Analysis

INTRODUCTION

Obesity is associated with a higher prevalence of various comorbidities including erectile dysfunction (ED). Bariatric surgery leads to weight loss and remission of weight-related diseases. The exact influence of bariatric treatment on ED is yet to be established; however, the number of papers on the subject is growing.

METHODOLOGY

A systematic review with meta-analysis comparing erectile dysfunction before and after surgery was conducted according to PRISMA guidelines with a literature search performed in June 2022. Inclusion criteria involved (1) ED assessment using the International International Index of Erectile Function (IIEF) and (2) longitudinal study design. Secondary endpoints involved hormonal changes and specific fields of IIEF.

RESULTS

An initial search yielded 878 records. Fourteen studies were included in the meta-analysis involving 508 patients. The quality of analyzed studies was moderate. Analysis showed significant differences in IIEF before and after surgery (Std. MD = 1.19, 95% CI 0.72 to 1.66, p<0.0001). Testosterone after surgery is higher by 156.32 pg/ml (95% CI 84.78 to 227.86, p<0.0001). There were differences in erectile function (MD:4.86, p < 0.0001), desire (MD: 1.21, p < 0.0001), intercourse satisfaction (MD: 2.16, p < 0.0001), and overall satisfaction (MD: 1.21, p = 0.003). There were no differences in terms of orgasms (MD: 0.65, p = 0.06).

CONCLUSION

There are differences in ED before and after bariatric surgery. Patients achieve 19% more in the IIEF questionnaire showing improvement. Further studies, including multivariate regression models on large cohorts, are required to determine whether the surgery is an independent factor in alleviating ED.

Effects of bariatric surgery on testosterone level and sexual function in men with obesity: A retrospective study

INTRODUCTION

Bariatric surgeries induce well-documented weight loss and resolve obesity comorbidities. Sexual function is one of the aspects of life quality and may benefit from surgery. Few studies have revealed the impact of bariatric surgeries on sexual function in Chinese men with obesity.

METHODS

This is a retrospective cohort study of patients undergoing bariatric surgery [laparoscopic sleeve gastrectomy (LSG) or laparoscopic Roux-en-Y gastric bypass (LRYGB)]. Data were collected between September 2017 and February 2022. The International Index of Erectile Function (IIEF) questionnaire was used to evaluate erectile function, intercourse satisfaction, orgasmic function, sexual desire, and overall satisfaction. Sex hormones and other blood tests were evaluated before and at least 1 year after the surgery.

RESULTS

Fifty-nine Chinese male patients completed the IIEF questionnaire. The multivariate logistic regression analysis revealed that body mass index (BMI) was the single independent risk factor of the severity of erectile dysfunction (ED). Preoperative testosterone levels had negative correlations with BMI and waist circumference. Thirty-seven patients completed the postoperative questionnaire with a mean follow-up of 23.2 months.

CONCLUSION

BMI and waist circumference were negatively correlated with testosterone levels. BMI was an independent risk factor for the severity of ED. LSG and LRYGB led to positive and sustained improvement in sexual function of men with obesity. The two procedures had a comparable effect, more subjects being needed. Sex hormone levels also could be reversible. However, more weight loss did not predict a positive change in sexual function. A greater BMI loss might predict a greater increase in testosterone.